### Grade 8 Maths Algebraic Expressions and Identities Multiple Choice Questions (MCQs)

1. **What are the co-efficients of y in the expression yz ^{2} + 5?**

(a) 5

(b) z

(c) z

^{2}

(d) None of these

2. **The constant term in the expression 1 + x ^{2} + x is**

(a) 1

(b) 2

(c) x

(d) x

^{2}

3. **The expression x + y – xy is:**

(a) Monomial

(b) Binomial

(c) Trinomial

(d) Quadrinomial

4. **From the following expressions 3ab, a ^{2}, b^{2}, a, 5ab, -2ab, 2a^{2} the three like terms are:**

(a) 3ab, 5ab, -2ab

(b) a

^{2}, a, 2a

^{2}

(c) 3ab, a

^{2}, b

^{2}

(d) 2a

^{2}, a

^{2}, a

5. **The value of expression 5n – 2, when n = -2 is:**

(a) -12

(b) 8

(c) 1

(d) -8

6. **If the length of each side of the equilateral triangle is l, then the perimeter of the equilateral triangle is:**

(a) 3l

(b) 3 + 1

(c) 3 – l

(d)

7. **Which of the following is trinomial:**

(a) 2a + 6b – 1

(b) 1

(c) 5a – 7

(d) a + b + c – 3

8. **The value of expression 5n ^{2} + 5n – 2 for n = -2 is**

(a) 13

(b) 3

(c) 8

(d) 12

9. **The expression for the statement: “y multiplied by 10 and then 7 added to product”.**

(a) 10 + y + 7

(b) 7y + 10

(c) 10y + 7

(d) 10y

10. **The numerical co-efficient of y in the expression 2x + 3y + 7z is:**

(a) 2

(b) 3

(c) 7

(d) 3y

11. **‘2’ is common factor of the expressions:**

(a) 12a^{2} b, 15ab^{2}

(b) 5xy, 10x

(c) 10x^{2}, -18x^{3}, 14x^{4}

(d) 33y, -22z

12. **The area of a rectangle is ‘xy’ where V is length and ly’ is breadth. If the length of rectangle is increased by 5 units and breadth is decreased by 3 units, the new area of rectangle will be:**

(a) (x – y)(x + 3)

(b) xy + 15

(c) (x + 5)(y – 3)

(d) xy + 5 – 3

13. **The product of a ^{2}, 2a^{2}, 5a^{10} is**

(a) 10 a

^{14}

(b) 7 a

^{14}

(c) 10 a

^{22}

(d) 10 a

^{40}

14. **Which of the following expression is trinomial:**

(a) xyz

(b) xy + z

(c) x + y + z

(d) x + yz

15. **Value of expression a(a ^{2} + a + 1) + 5 for ‘ a’ = 0 is:**

(a) a + 5

(b) 1

(c) 6

(d) 5

16. **Evalute (4x + y) ^{2} by suitable identity:**

(a) 4x

^{2}+ y

^{2}+ 8x

(b) 4x + y + 8xy

(c) 16x

^{2}+ y

^{2}+ 8xy

(d) 16x

^{2}+ y

^{2}+ 8

17. **(a – b) ^{2} is equal to:**

(a) a

^{2}+ b

^{2}– 2ab

(b) a

^{2}– b

^{2}+ 2ab

(c) a

^{2}– b

^{2}

(d) (a – b)(a + b)

18.** If ab = 6 and a + b = 5 then the value of (a ^{2} + b^{2}) is:**

(a) 11

(b) 12

(c) 13

(d) 16

19. **If x – y = 7 and xy = 9, then the value of (x ^{2} + y^{2}) is:**

(a) 64

(b) 67

(c) 63

(d) None of these

20. **If = 4, then the value of is:**

(a) 14

(b) 12

(c) 16

(d) None of these

### Class 8 Maths Algebraic Expressions and Identities Fill In The Blanks

1. The number of terms in the product of (3x^{2} + 6xy + 5y^{2}) and (3x + 4y – 13) is ……………….. .

2. In the product of (4a^{3} + 5a^{2} – 11a) and (-15 + 3a – 7a^{2}), the co-efficient of a^{4} is …………………… .

3. The value of (3a – 4b + 2) × (5a + 6) for a = 1 and b = -2 is ……………… .

4. The value of is ………………. .

5. Find the product: (A + B).(A – B).(A^{2} + B^{2}).(A^{4} + B^{4}) = ………………….. .

### Class 8 Maths Algebraic Expressions and Identities True(T) Or False(F)

1. If, a + = 7, then a^{2} + = 49

2. The product of a binomial and a trinomial will always have 5 terms.

3. (3x^{2} + 5y^{2}) × (5x^{5} + 8y^{3}) = 15x^{7} + 24x^{2}y^{3} + 25x^{5}y^{2} + 40y^{5}

### Class 8 Maths Algebraic Expressions and Identities Very Short Answer Type Questions

1. What are the co-efficients of y in the expression 4x – 3 y?

2. What is the statement for the expression 3mn + 5

3. What is the numerical co-efficient of y^{2} in the expression 2x^{2}y – 15xy^{2} + 7y

4. What must be subtracted from 2a + b to get 2a – b.

5. What must be added to 3x + y to get 2x + 3y?

6. What should be value of ‘a’ if y^{2} + y – a equals to 3 for y = 1?

### Class 8 Maths Algebraic Expressions and Identities Short Answer Type Questions

1. What must be added to 7z^{3} – 11z^{2} – 129 to get 5z^{2} + 7z – 92 ?

2. If (3x – 5y) = 10 and xy=5, then find the value of 9x^{2} + 25y^{2}.

3. If x + y = 9 and xy= 14, find x^{2} – y^{2}.

4. If 3x + 2y = 12 and xy = 6, find the value of 9x^{2} + 4y^{2}.

### Class 8 Maths Algebraic Expressions and Identities Long Answer Type Questions

1. Given (x^{2} + y^{2}) = 74 and xy = 35, find the value of x + y and x – y.

2. If x + = 4, find the value of

3. Using suitable identities evaluate the following:

(i) (93)^{2}

(ii) (12.5)^{2} – (7.5)^{2}

(iii) 93 × 109