Algebra: Formula, Identity, Questions
Tuhin Chakraborty
| Updated: Dec 3, 2020 10:12 IST
Algebra is also a very important section under the quantitative aptitude section, which holds a lot of weightage in various government competitive examinations such as banks, railways, and other state and central recruitment examinations. Many students find Algebra difficult as it requires remembering a lot of formulas and candidates need to know how to use them effectively for solving the problems asked in the examination.
In this article, we are going to cover the key concepts of Algebra along with the various types of questions candidates can expect in various upcoming government examinations, important formulas along with various tips and tricks. We have also included solved examples, practice questions that candidates can explore to become well versed with this section. Read the article thoroughly to clear all the doubts regarding the same.
What is Algebra?
The term “algebra” was derived from the word al-jabr. Algebra can be defined as the branch of mathematics in which we perform mathematical operations with the help of numbers (constants) and alphabets (variables). Let us understand different types of Algebraic questions one by one from below.
History of Algebra
Algebra is a branch of Mathematics that dates back centuries, to the Middle East. It was invented by a famous mathematician, astronomer, and geographer Abu Ja’far Muhammad ibn Musa al-Khwarizmi who was born about 780 in Baghdad. His book on Algebra is known as The Compendious Book on Calculation by Completion and Balancing. His book was translated into several languages and became very popular in the west.
Algebra uses letters and numbers. Algebra tends to find the unknown by putting the real-life variables into equations and then solving them by using various formulas or equations. Some of the sub-topics under Algebra are real numbers, complex numbers, matrices, vectors and so on.
After you’ve finished with Algebra, you can learn about Maths Average concepts in-depth here!
Types of Questions from Algebra
Let us see different types of questions that may come in the Algebra section one by one from below.
1. Algebraic Expressions
The combination of constants, variables and elementary arithmetic operations (+, -, ×,
÷) is called algebraic expression.
Example: \(3x + 5y, 4x^3 -5y \frac{1}{3} , 5x – 6y + 7z ÷ 8y\frac{1}{3}\) etc.
Algebraic Expressions can be further divided into two main categories. The types of algebraic expressions are as follows:
(a) On the basis of number of terms
These are the following types of algebraic expressions on the basis of number of terms:
(i) Monomial
The algebraic expression that consists of only one term is called a monomial.
Example: \(4x, 4\frac{y}{3}, -6.33z\) etc.
(ii) Binomial
The algebraic expression that consists of two terms is called binomial.
Example: \(2x + 3y, 4x + x^2\) etc.
(iii) Trinomial
The algebraic expression that consists of three terms is called trinomial.
Example: \(4xy + 3x + 5y^2\)
(iv) Polynomial
The algebraic expression that consists of two or more than two terms is called polynomial.
The general form of polynomial is given by P(x) = \(a_{0} + a_{1}x + a_{2}x^{2} + … +a_{n}x^{n}\)
Where, \(a_{0}, a_{1}, a_{2}, a_{3} … and a_{n}\), are real numbers and n is a whole number (non negative integer).
Example: \(1 + 2x – 3x^2 + 5x^4, 6x^3 – 2x^2 + 4\) etc.
(b) On the basis of degree of a polynomial
(i) Linear Polynomial
The polynomial in which the highest power of the variables is one or, the polynomial of degree 1 is called linear polynomial.
Example: 2x + 3
(ii) Quadratic Polynomial
The polynomial of degree two is called quadratic polynomial.
Example: \(x^2 – 4x + 5, x^2 – 5\) etc.
(iii) Cubic Polynomial
The polynomial of degree three is called cubic polynomial.
Example: \(x^3 + 4x^2 – 3x + 4, x^3 – 4x – 3\) etc.
(iv) Quartic Polynomial
The polynomial of degree four is called the quartic equation.
Example: \(5x^4 – 4x + 2, 5x^4 + 4x^3 – 3x\) etc.
2. Equations
When we equate an expression or polynomial with a number, then the resultant is called an equation.
There are following types of equations:
(a) Linear Equation in One Variable
The equation having only one variable with highest power 1 is called a linear equation in one variable.
The general form of linear equation in one variable is ax + b = 0, where a and b are real constants and a ≠ 0
Example: \(23 + x = 30\)
(b) Linear Equation in Two Variables
The equation having two variables with the highest power of the variable 1 is called linear equation in two variables.
The general form of the linear equation in two variables is given by ax + by + c = 0, where a, b and c are real numbers and (a, b) ≠ (0, 0).
Example: \(12x + 23y = 30\)
(c) Quadratic Equation
An equation of the form \(ax^2 + bx + c = 0\) is called a quadratic equation.
The standard form of the quadratic equation is \(ax^2 + bx + c = 0\), where a, b and c are real numbers and a ≠ 0
Example: \(4x^2 + 2x + 1 = 0, 5x^2 – 2x + 4 = 0 \) etc.
(d) Cubic Equation
An equation of the form \(ax^3 + bx^2 + cx + d = 0\) is called a cubic equation. Where a, b, c, and d are real constants and a ≠ 0.
How to Solve Algebra Questions – Tips and Tricks
Candidates can find different tips and tricks below for solving the questions related to Algebra.
Tip # 1: Definition of Coefficient – The number or the fixed value multiplied to the variable in a term of an algebraic expression is called the coefficient of the term.
Example: In polynomial \(4x^3 + 5x^2 – 7x – 2\), the coefficient of \(x^3\) is 4, coefficient of \(x^2\(\) is 5, coefficient of x is -7 and the constant term is -2.
Tip # 2: Definition of Degree of Polynomial – The highest power of the variables in a polynomial is called the degree of polynomial.
Example: The degree of polynomial \(\)4x^3 + 5x^2 – 7x – 2\) is 3, the degree of polynomial \(1 + 2x – 3x^2 + 5x^4\) is 4.
Tip # 3: Zeros of Polynomial – Those value(s) of x(variable) which satisfy the polynomial is/ are called the zero/zeros of the polynomial.
Example: since x = 2 satisfies the polynomial \(x^2 – 5x + 6\), so we can say that x = 2 is a zero of polynomials.
Tip # 4: Remainder Theorem – When P(x) is divided by (x – a), then remainder will be P(a).
Example: when P(x) = \(x^2 -3x + 6\) is divided by (x – 2), then remainder will be P(2)
⇒ P(2) = 22 – 3 × 2 + 6 = 4
Tip # 5: Factor Theorem – If (x – a) is a factor of P(x), then remainder will be zero i.e. P(x) = 0
Example: Find the value of k if x – 2 is a factor of \(x^2 – k x + 6 \)
Solution: according to question P(2) = 0 ⇒ 22 – k × 2 + 6 = 0
Hence, k = 5
Tip # 6: The value of the variables that satisfies the equation is called the solution of the equation. The graph of the linear equation ax + by + c = 0 is a straight line.
Example: since, x = 2 and y = 1 satisfy the linear equation in two variables x – 4y + 2 = 0, so we can say that x = 2 and y = 1 is a solution of the above equation.
Tip # 7: A system of a pair of linear equations in two variables is said to be consistent if it has at least one solution. A system of a pair of linear equations in two variables is said to be inconsistent if it has no solution.
Tip # 8: The system of a pair of linear equations \(a_{1}x + b_{1}y + c_{1} = 0\) and \(a_{2}x + b_{2}y + c_{2} = 0\) has:
A unique solution (i.e. consistent) if: \(\frac{a_1}{a_2}\) is not equals to \(\frac{b_1}{b_2}\)
In this case the graphs of the pair of linear equations intersect at only one point and the coordinate of points is the solution of the pair of linear equations.
No solution (i.e. inconsistent) if:
\(\frac{a_1}{a_2}\) is equals to \(\frac{b_1}{b_2}\) not equals to \(\frac{c_1}{c_2}\)
In this case the graphs of the linear equations are parallel to each other, that is the lines do not intersect each other.
III. An infinite number of solution (i.e. consistent) if:
\(\frac{a_1}{a_2}\) is equals to \(\frac{b_1}{b_2}\) is also equals to \(\frac{c_1}{c_2}\)
In this case the graphs of the linear equations coincide with each other, that is the lines overlap each other.
Tip # 9: Root of Equation – The value(s) of x which satisfy the equation is/are called the root of the equation.
Maximum number of real roots of a linear, quadratic, cubic and a quartic equation are 1, 2, 3 and 4 respectively.
Example: x = 3, satisfy the equation \(x^2 – 6x + 9 = 0\), so we can say that x = 3 is a root of the equation.
Tip # 10: To solve a quadratic equation by the help of quadratic formula method, we first need to find the discriminant (D), where, \(D = b^2 – 4ac\).
- If D > 0, then the roots of the quadratic equation are real and distinct.
- If D = 0, the roots of the quadratic equation are real and equal.
- If D < 0, the roots of the quadratic equation are imaginary.
Tip # 11: Usually we denote the roots of quadratic equations by α and β, where α + β = \(-\frac{b}{a}\)and α × β = \(\frac{c}{a}\)
Tip # 12: If it is given that α and β are the roots of the quadratic equation, then we can find the quadratic equation by the help of the formula \(x^2 – (α + β)x + αβ = 0\)
Example: if x = 3 and x = 4 are the roots of a quadratic equation then we can find the equation by taking α = 2 and β = 4.
α + β = 7, α.β = 3 × 4 = 12
So, the required quadratic equation is x2 – 7x + 12 = 0
Tip # 13: If α, β and δ are the roots of equation ax3 + bx2 + cx + d = 0, then α + β + δ = -b/a, αβ + βδ + δα = c/a and αβδ = -d/a
Tip # 14: If α, β and δ are the roots of a cubic equation, then we can find the equation by using the formula x3 – (α + β + δ)x2 + (αβ + βδ + δα)x – αβδ = 0
Tip # 15: We can find the roots of quadratic equations by the help of factorization method, and quadratic formula method.
Uses of Algebra in Real life
Algebra is used in various fields such as DBMS (Database Management System), Medicine, Architecture and Accounting. Algebra can also be used for everyday problem-solving and developing critical thinking such as logic, patterns, and deductive and inductive reasoning or understanding the core concepts of algebra can prove to be beneficial to everyone to solve the complex problems which involve numbers.
It plays a major role in solving various problems in the workplace where real-life scenarios of unknown variables involve expenses and profits calculation related to employees. Algebraic equations can be used to determine the missing factors in these scenarios.
Some Important Basic Algebra Formulas
Below candidates can find some of the frequently used formulas in Algebra to solve questions.
| \((a + b)^2 = a^2 + 2ab + b^2\) |
| \((a – b)^2 = a^2 – 2ab + b^2\) |
| \((a + b)^2 = (a – b)^2 + 4ab\) |
| \((a – b)^2 = (a + b)^2 – 4ab\) |
| \(a^2 + b^2 = (a + b)^2 – 2ab\) |
| \(a^2 + b^2 = (a – b)^2 + 2ab\) |
| \(a^2 – b^2 = (a + b) (a – b)\) |
| \(a^3 + b^3 = (a + b) (a^2 – ab + b^2)\) |
| \(a^3 – b^3 = (a – b) (a^2 + ab + b^2)\) |
| \((a + b)^3 = a^3 + b^3 + 3ab (a + b)\) |
| \((a – b)^3 = a^3 – b^3 – 3ab (a – b)\) |
| \(a^3 + b^3 = (a + b)^3 – 3ab (a + b)\) |
| \(a^3 – b^3 = (a – b)^3 + 3ab (a – b)\) |
| \((a + b + c)^2 = a^2 + b^2 + c^2 + 2ab + 2bc + 2ca\) |
| \(a^3 + b^3 + c^3 – 3abc = (a + b + c) (a^2 + b^2 + c^2 – ab – bc – ac) = ½ (a + b + c)[(a – b)^2 + (b – c)^2 + (c – a)^2]\) |
| \(a^3 + b^3 + c^3 = 3abc If (a + b + c) = 0\) |
| \((a + b + c)3 = a^3 + b^3 + c^3 + 3(a + b)(b + c)(c + a)\) |
| \(a^4 + b^4 + a^2b^2 = (a^2 – ab + b^2)(a^2 + ab + b^2)\) |
| If \(x^2 + y^2 + z^2 = 0, then x = y = z = 0\) |
| If \(a^3 + b^3 + c^3 = 3abc Then (a + b + c) = 0\) |
| If xy = 1, then 1/(x+1) + 1/(y+1) = 1 |
Download Algebra Formulas PDF
Other Important Formulas
Apart from all the formulas mentioned above candidates can find an Algebra formulas cheat sheet filled with shortcut formulas which candidates can use to solve the questions related to Algebra quickly.
Notes: For solving questions related to long roots, candidates can follow the below-mentioned formulas.
For the two forms mentioned below, if the difference between the factors of x is 1, then
the factor which is greater in value will be the answer of the given question.
Also, learn about Maths Average formula here once you are through with Algebra basics concepts!
Algebra Sample Questions with Answers
Question 1: If (a – 2)2 + (b + 3)2 + (c – 5)2 = 0, then find the value of a – b – c.
Solution: Given: (a – 2)2 + (b + 3)2 + (c – 5)2 = 0
So, a – 2 = 0 ⇒ a = 2
And, b + 3 = 0 ⇒ b = -3
And, c – 5 = 0 ⇒ c = 5
Therefore, a – b – c = 2 – (-3) – 5 = 0
Question 2: If (2x + 3)3 + (x – 8)3 + (x + 13)3 = (2x + 3) (3x – 24) (x + 13), then what is the value of x?
Solution: As we know,
If x3 + y3 + z3 – 3xyz = 0, then x + y + z = 0
⇒ (2x + 3)3 + (x – 8)3 + (x + 13)3 = (2x + 3) (3x – 24) (x + 13)
⇒ (2x + 3)3 + (x – 8)3 + (x + 13)3 – 3 (2x + 3) (x – 8) (x + 13) = 0
⇒ (2x + 3) + (x – 8) + (x + 13) = 0
⇒ 4x + 8 = 0
⇒ 4x = -8
⇒ x = -8/4 = -2
Question 3: If x + 1/x = 2 then find the value of x^5 + 1/x^5
Solution: Given: x + 1/x = 2
So, x = 1
So, x^5 + 1/x^5 = 1 + 1/1 = 2
Question 4: If x + 1/x = -2 then find the value of x^5 + 1/x^5 and x^4 + 1/x^4
Solution: Given: x + 1/x = 2
So, x = -1
So, x^5 + 1/x^5 = 1 + 1/1 = -2 and x^4 + 1/x^4 = 2
Question 5: If x + 1/x = 2, then find the value of x^2 + 1/x^2
Solution: x^2 + 1/x^2 = 2
Question 6: If x + 1/x = 5, then find the value of x^3 – 1/x^3
Solution: x^3 – 1/x^3 = 5^3 + 3 x 5 = 140
Question 7: If x + 1/x = 1, then find the value of x^20 – 1/x^20
Solution: Given: x + 1/x = 1
So, x = -1
x^20 – 1/x^20 = 2
Question 8: If x + 1/x = -1, then find the value of x^20 – 1/x^20
Solution: Given: x + 1/x = -1
So, X = +1
x^20 – 1/x^20 = 0
Question 9: If x + 1/x = 5, then find the value of x^3 + 1/x^3
Solution: x^3 + 1/x^3 = 5^3 – 3 x 5 = 110
Question 10: Find the value of 
Solution: 
= 3
Exams where Algebra is Part of Syllabus
Questions based on Algebra come up often in various prestigious government exams some of them are as follows:
- SBI PO, SBI Clerk, IBPS PO, IBPS Clerk
- SSC CGL, SSC Steno, SSC 10+2
- LIC AAO, LIC ADO
- RRB
- UPSC
- MPSC
- KPSC
- BPSC
- WBPSC
- Other State Level Recruitment Examinations
| If you are checking Algebra article, also check the related maths articles in the table below: | |
| Indefinite Integrals | Definite Integrals |
| Integral Calculus | Algebra |
| Algebraic Identities | Vector Algebra |
We hope you found this article regarding algebra was informative and helpful, and please do not hesitate to contact us for any doubts or queries regarding the same. You can also download the Testbook App, which is absolutely free, and start preparing for any government competitive examination by taking the mock tests before the examination to boost your preparation.
| If you are checking Algebra article, also check the related maths articles in the table below: | |
| Number System | Averages |
| Pie Chart | Quadratic Equation |
| Lines | Probability |
Algebra FAQs
Q.1 What is Algebra?
Ans.1
Algebra is the branch of mathematics in which we perform mathematical operations with the help of numbers (constants) and alphabets (variables).
Q.2 How many types of questions asked from Algebra?
Ans.2
A few types of questions that candidates can expect from the Algebra section of quantitative aptitude section can be found above.
Q.3 Where will I get the tips and tricks for Algebra?
Ans.3
Some of the tips and tricks regarding the algebra section are given above in the article.
Q.4 Where I will find some of the sample questions related to Algebra?
Ans.4
Various example questions along with their solutions are given above in the article. Kindly go through the article for the same.
Q.5 In which exam questions from Algebra come up?
Ans.5
Algebra comes in various government competitive examinations on a regular basis. The names of such examinations are given above in the article.
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