Class 8 Maths MCQ – Algebraic Expressions and Identities

This set of Class 8 Maths Chapter 9 Multiple Choice Questions & Answers (MCQs) focuses on “Algebraic Expressions and Identities”. These MCQs are created based on the latest CBSE syllabus and the NCERT curriculum, offering valuable assistance for exam preparation.

1. Identify the like terms: 3ab – 4b2 – 6ab.
a) 3ab, -6ab
b) -4b2, 3ab
c) 3ab, 6ab
d) -4b2, 6ab

Explanation: An algebraic expression is combination of terms with algebraic operations like addition, subtraction, multiplication. The terms having same literal factors are called like terms. Like terms are formed from same variables and the powers of the variables are similar. But, coefficients of the like terms can be different. Eg: 2x, 3x form a pair of like terms; 5ax, -ax form a pair of like terms.

2. Identify the like terms: 4xy – 3y + 44y.
a) -3y, 44y
b) 4xy, 44y
c) -44y, -3y
d) 3y, 44y

Explanation: An algebraic expression is combination of terms with algebraic operations like addition, subtraction, multiplication. The terms having same literal factors are called like terms. Like terms are formed from same variables and the powers of the variables are similar. But, coefficients of the like terms can be different. Eg: 2x, 3x form a pair of like terms; 5ax, -ax form a pair of like terms.

3. Identify all the unlike terms: 2a – 3b – 4c.
a) 2a, 4c
b) 2a, 3b, 4c
c) 2a, -3b, 4c
d) 2a, -3b, -4c

Explanation: An algebraic expression is combination of terms with algebraic operations like addition, subtraction, multiplication. The terms which are not having same literal factors are called unlike terms. Unlike terms have different variables and the powers of the variables can be different. But, coefficients of the like terms can be different. Eg: 3x, 4yx form a pair of like terms; 5ax, -ax form a pair of like terms.

4. Identify the like terms: 3a2b + 4b2a – ba2.
a) 3a2b, 4b2a
b) 3a2b, -ba2
c) 3a2b, ba2
d) 4b2a, -ba2

Explanation: An algebraic expression is combination of terms with algebraic operations like addition, subtraction, multiplication. The terms which are not having same literal factors are called unlike terms. Unlike terms have different variables and the powers of the variables can be different. But, coefficients of the like terms can be different. Eg: 3x, 4yx form a pair of like terms; 5ax, -ax form a pair of like terms.

5. What will be the result if the expressions 2x – 4x2y and 16y2x + 2x2y are added?
a) 2x – 4x2y + 18x2y
b) 2x – 2x2y + 16y2x
c) 2x – 2x2y – 16y2x
d) 2x + 4x2y + 18x2y

Explanation: The terms of an algebraic expression having same literal factors are called like terms and those terms with different literal factors are called unlike terms. While addition or subtraction of polynomials, like terms are added/subtracted first and then unlike terms are handled. In the given expressions, -4x2y and 2x2y are like terms.
⇒ (2x – 4x2y) + (16y2x + 2x2y) = 2x – 4x2y + 2x2y + 16y2x (Collecting like terms)
⇒ (2x – 4x2y) + (16y2x + 2x2y) = 2x – 2 x2y + 16y2x (Adding like terms).
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6. Find the value the following expression: 1/6x + 2/5xy – 13y – 7/5xy + 1/6x.
a) 1/3x – 9/5xy – 13y
b) 1/3x + 1xy – 13y
c) 1/3x – 1xy – 13y
d) -1xy – 13y

Explanation: 1/6x + 2/5xy – 13y – 7/5xy + 1/6x = 1/6x + 1/6x + 2/5xy – 7/5xy – 13y (Collecting like terms)
= 1/3x – 1xy – 13y (Adding like terms).

7. Subtract the following expression: 22ab – 30a2b + 2b from 50a2b – 6b2a – 5b.
a) 22ab – 80a2b – 6b2 – 7b
b) 80a2b – 6b2a + 7b – 22ab
c) 80a2b – 6b2a – 7b – 22ab
d) 80a2b + 6b2a – 7b

Explanation: (50a2b – 6b2a – 5b) – (22ab – 30a2b + 2b) = 50a2b – 6b2a – 5b – 22ab + 30a2b + 2b
= 50a2b + 30a2b – 6b2 – 5b – 2b (Collecting like terms)
= 80a2b – 6b2 – 7b22ab (Adding/subtracting like terms).

More MCQs on Class 8 Maths Chapter 9:

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