Maths Quiz for Class 8 Algebraic Expressions

Maths Quiz for Class 8 Algebraic Expressions

In this post, we are providing 20 online maths quiz questions for class 8 algebraic expressions. Online maths quiz will take around 20 minutes to complete it.

Question 1: The degree of the polynomial 3x⁵ – 5x⁴y² – 2x³ + 8x – 7 is __________.

A) 4

B) 5

C) 6

D) 7

Explanation: The degree of the polynomial 3x⁵ – 5x⁴y² – 2x³ + 8x – 7 is 6. Because the degree of the second term = 4 + 2 = 6.

Question 2: Which of the following algebraic expressions is a binomial?

A) 3x – 4x × 2y

B) 3x × 5y

C) 4x × 2y × 3z

D) 2x

Explanation: 3x – 4x × 2y is a binomial because 3x – 4x × 2y = 3x – 8xy.

Question 3: Which of the following algebraic expressions is not a polynomial?

A) 2x³ + 4x² – 1/x

B) 5x² – 3x + 2

C) 3x² + 5

D) 7x² – 4x + 3

Explanation: 2x³ + 4x² – 1/x is not a polynomial because it last term is -1/x, in which the power of x is -1. But in a polynomial, the power of variable should be positive integers.

Question 4: Which of the following algebraic expressions is a trinomial?

A) 5x + 2x × 3y

B) 2x – 3x + 4z

C) 3x × 2x + 5y

D) x × 2y × 3z

Explanation: 2x – 3x + 4z is a trinomial because it has 3 terms.

Question 5: Which of the following pairs are like terms?

A) 7x, 7y

B) 5x, -3x

C) -3y, 3x

D) -5x, -5a

Explanation: 5x and -3x are like terms because both have the same literal factor x.

Question 6: Write the numerical coefficient of the term -xyz.

A) -2

B) 1

C) -1

D) 2

Explanation: The numerical coefficient of the term -xyz is -1.

Question 7: Find the coefficient of y in the term -3x²yz.

A) 3x²z

B) -3x²z

C) -3x²

D) 3x²

Explanation: The coefficient of y in the term -3x²yz is -3x²z.

Question 8: Evaluate 5x³ – 3x² + 7x – 9 for x = –2.

A) 5

B) -5

C) 75

D) -75

Explanation: Putting x = -2 in 5x³ – 3x² + 7x – 9, we get 5(-2)³ – 3(-2)² + 7(-2) – 9 = 5 × -8 – 3 × 4 + 7 × -2 – 9 = –40 – 12 – 14 – 9 = -75

Question 9: Find the value of 2x² + 4x – 7 if x = –3.

A) -1

B) 1

C) -37

D) 23

Explanation: Putting x = -3 in 2x² + 4x – 7, we get 2x² + 4x – 7 = 2(-3)² + 4(-3) – 7 = 2 × 9 + 4 × -3 – 7 = 18 – 12 – 7 = 18 – 19 = -1

Question 10: Evaluate 2x²y – 3y²x + 4xy – 15 for x = -2 and y = -1.

A) -7

B) 7

C) -9

D) 9

Explanation: 2x²y – 3y²x + 4xy – 15 = 2(-2)²(-1) – 3(-1)²(-2) + 4(-2)(-1) – 15 = -8 + 6 + 8 – 15 = -9

Question 11: Add 2ab – 6bc + 3ca, 6bc – 9, 4abc – 2ab + 3bc and 2ca – 6.

A) 3bc + ca + 4abc – 15

B) 3bc + 5ca + 4abc – 15

C) 3bc + 5ca + abc – 15

D) 3bc + 5ca + 4abc – 9

Explanation: 2ab – 6bc + 3ca + 6bc – 9 + 4abc – 2ab + 3bc + 2ca – 6 = 2ab – 2ab – 6bc + 6bc + 3bc – 9 + 4abc + 3ca + 2ca – 6 = 3bc + 5ca + 4abc – 15

Question 12: Subtract 4ab – 3bc from ab – bc.

A) 3bc – 2ab

B) 2bc – 3ab

C) 2bc + 3ab

D) -2bc + 3ab

Explanation: (ab – bc) – (4ab – 3bc) = ab – bc – 4ab + 3bc = ab – 4ab – bc + 3bc = 2bc – 3ab

Question 13: Subtract the sum of 5a – 3b + 4c – 8 and –6b + 3c from the sum of 7b – 4c + 10 and 2a – b + 3c – 5.

A) -3a + 15b – 8c + 13

B) -3a + 15b – 6c + 13

C) 7a + 15b – 8c + 13

D) -3a – 3b – 8c + 13

Explanation: Sum of 5a – 3b + 4c – 8 and –6b + 3c = 5a – 3b + 4c – 8 – 6b + 3c = 5a – 9b + 7c – 8. Sum of 7b – 4c + 10 and 2a – b + 3c – 5 = 7b – 4c + 10 + 2a – b + 3c – 5 = 2a + 6b – c + 5. Now, (2a + 6b – c + 5) – (5a – 9b + 7c – 8) = 2a + 6b – c + 5 – 5a + 9b – 7c + 8 = -3a + 15b – 8c + 13

Question 14: The number of like terms in 5x²y – 3xy² + 2x²y – 4yx + 8xyz is ______.

A) 0

B) 1

C) 3

D) 2

Explanation: 5x²y – 3xy² + 2x²y – 4yx + 8xyz has 2 like terms.

Question 15: Multiply 2xy³ and 4x²y².

A) 8x²y⁵

B) 8x³y⁴

C) 8x³y⁵

D) 8x²y⁴

Explanation: 2xy³ × 4x²y² = 8x¹⁺²y³⁺² = 8x³y⁵

Question 16: Find the product of 4xy – 3yz + 6xz and 2xy.

A) 8x²y² – 6xy²z + 12xyz

B) 8x²y² – 6xy²z + 12x²yz

C) 8x²y² – 6xyz + 12x²yz

D) 8x²y – 6xy²z + 12x²yz

Explanation: (4xy – 3yz + 6xz) × 2xy = 4xy × 2xy – 3yz × 2xy + 6xz × 2xy = 8x²y² – 6xy²z + 12x²yz

Question 17: Evaluate after simplification: abc (a² + b² + c²) for a = 1, b = 2, c = 3.

A) 59

B) 58

C) 56

D) 55

Explanation: abc (a² + b² + c²) = a³bc + ab³c + abc³ = (1)³(2)(3) + (1)(2)³(3) + (1)(2)(3)³ = 6 + 24 + 29 = 59

Question 18: Find the product of (2x + 3y) and (5x – 4y).

A) 10x² – 7xy + 12y²

B) 10x² + 7xy + 12y²

C) 10x² + 7xy – 12y²

D) 10x² – 7xy – 12y²

Explanation: (2x + 3y) × (5x – 4y) = 2x × 5x + 2x × -4y + 3y × 5x + 3y × -4y = 10x² – 8xy + 15xy – 12y² = 10x² + 7xy – 12y²

Question 19: Simplify x (x + y + z) – y (y – x + z).

A) x² – y² + 2xy

B) x² – y² + 2xy + zx – yz

C) x² – y² + zx – yz

D) x² – y² + 2xy – yz

Explanation: x (x + y + z) – y (y – x + z) = (x × x + y × x + z × x) – (y × y – x × y + z × y) = (x² + xy + zx) – (y² – xy + yz) = x² + xy + zx – y² + xy – yz = x² – y² + 2xy + zx – yz

Question 20: Simplify 4pq (p² + q²) – 4pq (p² – q²).

A) 8p³q

B) 8pq²

C) 8pq³

D) 4pq³

Explanation: 4pq (p² + q²) – 4pq (p² – q²) = 4pq × p² + 4pq × q² – 4pq × p² + 4pq × q² = 4p³q + 4pq³ – 4p³q + 4pq³ = 8pq³

Report Card

Total Questions Attempted: 0

Correct Answers: 0

Wrong Answers: 0

Percentage: 0%