Class 7 Maths Algebraic Expressions Important Questions For Exam
IMPORTANT QUESTIONS FOR CBSE EXAMINATION | CLASS 7 MATHEMATICS
ALGEBRAIC EXPRESSIONS – Chapter 12
Answer the following (2 marks)
1. Identify, in the following expressions, terms which are not constants. Give their numerical coefficients:
ab + 5, xyz – 13, 4x – 3y +3, a + b + 8
2. What are the coefficients of x in the following expressions?
3x – 5y, 6- x+ y, 2y – 3xz
3. Group the like terms together from the following:
12x, 12, -25x, -25, -25y, 1, x, 12y, y.
4. Classify the following expressions as a monomial, a binomial, or a trinomial:
x+y, xy + x + y, x + y – 5, ab, ab + 5, 4pq – 3q + 5p, 6, 4mn + 8
5. State with reasons, which of the following pairs of terms are of like terms and which are of unlike terms:
i. 6a, 11b
ii. 10x, -21x
iii. -3ab, 7ba
iv. 3mn, 3m
6. Get the algebraic expressions in the following cases using variables, constants and arithmetic operations.
i. Subtraction of y from x.
ii. The number p multiplied by itself.
iii. Sum of the numbers x and y subtracted from their product.
iv. Number 2 is added to twice the product of x and y.
7. Add and subtract:
i. x – y, x + y
ii. ab + 4, ab – 8
8. Simplify combining like terms:
i. 12x – 8 + 7x – 2x
ii. a + b – 2 + b – 2 + a – 2b
9. Find the values of the following expressions for x = 2.
i. x + 8
ii. 3x – 12
10. Find the value of the following expressions for a = 3, b = 2
i. 3a – 2b
ii. 3a + b
ANSWERS:
1.
3. Like terms are
i. 12x, -25 x, x
ii. 12, -25, 1
iii. -25y, 12y, y
4. Monomials are ab, 6
Binomials are x + y, ab + 5, 4mn + 8.
Trinomials are xy + x + y, x + y – 5, 4pq – 3q + 5p.
5. i. 6a and 11b are unlike terms because the variables in the terms are different.
ii. 10x and -21x are like terms because algebraic factors are same.
iii. -3ab and 7ba are like terms because algebraic factors are same (Remember ab = ba)
iv. 3mn and 3m are unlike terms because the variables in the terms are different.
6. i. x – y
ii. p x p
iii. xy – (x + y)
iv. 2 + 2xy
7. i. x – y + x + y = x + x – y + y = 2x
x – y – (x + y) = x – y – x – y = x – x – y – y = 0 – 2y = -2y
iiab + 4 + ab – 8 = ab + ab + 4 – 8 = 2ab – 4
ab +4 – (ab – 8) = ab + 4 – ab + 8 = ab – ab + 4 + 8 = 0 + 12 = 12
8. i. 12x +7x- 2x – 8 = 17x -8
ii. a + a + b + b – 2b – 2 – 2 = 2a + 2b – 2b – 4 = 2a – 4
9. When x = 2,
i. x + 8 = 2 + 8 = 10
ii. 3x – 12 = 3 x 2 – 12 = 6 – 12 = -6
10. Put a = 3 and b = 2
i. 3a – 2b = 3 x 3 – 2x 2 = 9 – 4 = 5
ii. 3a + b = 3 x 3 +2 = 9 + 2 = 11.
