Class 8 Maths Chapter 9 Algebraic Expressions and Identities MCQs

Class 8 Maths Chapter 9 Algebraic Expressions and Identities MCQs (Questions and Answers) are provided online here for students. These multiple-choice questions have been designed by experts referring to the latest CBSE syllabus (2022-2023) and NCERT guidelines. The objective questions are provided chapter-wise at BYJU’S. Also, learn important questions for class 8 Maths here.

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MCQs Questions on Class 8 Algebraic Expressions and Identities

Multiple choice questions (MCQs) are available for Class 8 chapter 9 Algebraic Expressions and Identities chapter. For all the problems, there are four multiple options given among which one is the right answer. Solve each question and choose the correct answer.

1. An algebraic expression that contains only one term is called:

A. Monomial

B. Binomial

C. Trinomial

D. None of the above

Answer: A

Example: 2x is a monomial

2. 5x+6y is a:

A. Monomial

B. Binomial

C. Trinomial

D. None of the above

Answer: B

Explanation: The expression containing two terms is called binomial.

3. The algebraic expression 3x+2y+6 is a:

A. Monomial

B. Binomial

C. Trinomial

D. None of the above

Answer: C

Explanation: The algebraic expression containing three terms is called a trinomial. Here, 3x, 2y and 6 are three terms.

4. A polynomial contains _______ number of terms:

A. One

B. Two

C. Three

D. Any

Answer: D

Explanation: A polynomial can contain any number of terms, i.e. one or more than one.

5. In which of the following, the two expressions are like terms?

A. 7x and 7y

B. 7x and 9x

C. 7x and 7x²

D. 7x and 7xy

Answer: B

6. If we add, 7xy + 5yz – 3zx, 4yz + 9zx – 4y and –3xz + 5x – 2xy, then the answer is:

A. 5xy + 9yz +3zx + 5x – 4y

B. 5xy – 9yz +3zx – 5x – 4y

C. 5xy + 10yz +3zx + 15x – 4y

D. 5xy + 10yz +3zx + 5x – 6y

Answer: A

Explanation: Given, 7xy + 5yz – 3zx, 4yz + 9zx – 4y and –3xz + 5x – 2xy.

If we add the three expressions, then we need to combine the like terms together.

(7xy – 2xy) + (5yz + 4yz) – 3zx + 9zx – 3xz – 4y + 5x

= 5xy + 9yz + 3zx + 5x – 4y

7. If we subtract 4a – 7ab + 3b + 12 from 12a – 9ab + 5b – 3, then the answer is:

A. 8a+2ab+2b+15

B. 8a+2ab+2b-15

C. 8a-2ab+2b-15

D. 8a-2ab-2b-15

Answer: C

Explanation: (12a – 9ab + 5b – 3) – (4a – 7ab + 3b + 12)

= 12a – 9ab + 5b – 3 – 4a + 7ab -3b-12

= (12 – 4)a – (9 – 7)ab + (5 – 3)b – 3 – 12

= 8a – 2ab + 2b – 15

8. If we multiply 5x and (– 4xyz), then we get:

A. 20x²yz

B. -20x²yz

C. x²yz

D. -2xyz

Answer: B

Explanation: (5x) x (-4xyz)

= 5 × x × (-4) × x × y × z

= -20x¹⁺¹yz

= -20x²yz

9. The product of 4x and 0 is:

A. 4x

B. 4

C. 0

D. None of the above

Answer: C

Explanation: Any value multiplied by zero is zero.

10. The volume of a cuboid with length, breadth and height as 5x, 3x² and 7x⁴ respectively is:

A. 105x⁷

B. 105x²

C. 105x⁴

D. 105x

Answer: A

Explanation: Volume of cuboid = Length × breadth × height

V = 5x × 3x² × 7x⁴

V = 105 x¹⁺²⁺⁴

V = 105x⁷ cubic units

11. The product of 5x and 3y is:

A. xy

B. 2xy

C. 5xy

D. 15xy

Answer: (D) 15xy

(5x)(3y) = 15xy

12. The product of 6x and -11x is:

A. 66x²

B. -66x²

C. x²

D. -x²

Answer: B. -66x²

(6x) (-11x) = –66x²

13. The area of a rectangle whose length and breadth are 3y and 9y² respectively is:

A. 12y³

B. 21y³

C. 27y³

D. y³

Answer: C. 27y³

Explanation:

Area of rectangle = length x breadth = 3y x 9y² = 27y³.

14. The area of a rectangle that has length = 2a²b and breadth = 3ab² is:

A. 6a³b³

B. a³b³

C. 2a³b³

D. 4a³b³

Answer: A. 6a³b³

Explanation:

Area of rectangle = (2a²b)(3ab²) = 6a³b³

15. The side of a cube is 2a. Find the volume of the cube.

A. 4a²

B. 2a

C. 8a³

D. 8

Answer: C. 8a³

Explanation:

Volume of the cube = 2a × 2a × 2a = 8a³

16. Multiplication of monomials x², (–x)³, (–x)⁴ is equal to:

A. x⁹

B. x⁵

C. x⁷

D. x⁶

Answer: A. x⁹

Explanation:
(x²).(-x³).(-x)⁴ = x⁹

17. The value of (x – y)(x + y) + (y – z)(y + z) + (z – x) (z + x) is:

A. x + y + z

B. x² + y² + z²

C. xy + yz + zx

D. 0

Answer: D. 0

Explanation:

(x – y)(x + y) + (y – z)(y + z) + (z – x) (z + x)

= x² – y² + y² – z² + z² – x²               [By algebraic identity: a² – b² = (a+b) (a-b)]

= 0

18. (a – b)² is equal to:

A. a² + b² – 2ab

B. a² + b² + 2ab

C. a² + b²

D. 2ab

Answer: A. a² + b² – 2ab

Explanation: By algebraic identity,

(a + b)² = a² + b² – 2 ab

19. The product of 3xy²z and 4x is:

A. 12xyz

B. 12xy²

C. 12x²y²z

D. 12x²yz

Answer: C. 12x²y²z

Explanation: The product of 3xy²z and 4x is:

⇒ (3xy²z) (4x)

⇒ 3.x.y².z.4.x

⇒ 12x²y²z

20. Which of the following is a like term as 8xy?

A. 8

B. 8x

C. 8y

D. xy

Answer: D. xy