Algebraic Expressions and Operations on them Class 7 Practice Set 35 Answers Solutions Chapter 8
Question 1
Maharashtra Board Solution
Multiply: i. 16xy × 18xy ii. 23xy² × 4yz² iii. (12a + 17b) × 4c iv. (4x + 5y) × (9x + 7y)
Solution & Step-by-Step Answer:
i. 16xy × 18xy = 16 × 18 × xy × xy = 288x²y²
ii. 23xy² × 4yz²
= 23 × 4 × xy² × yz²
= 92xy³z²
iii. (12a + 17b) × 4c = 12a × 4c + 17b × 4c
= 48ac + 68bc
iv. (4x + 5y) × (9x + 7y)
= 4x × (9x + 7y) + 5y × (9x + 7y)
= (4x × 9x) + (4x × 7y) + (5y × 9x) + (5y × 7y)
= 36x² + 28xy + 45xy + 35y²
= 36x² + 73xy + 35y²
Question 2
Maharashtra Board Solution
A rectangle is (8x + 5) cm long and (5x + 3) cm broad. Find its area.
Solution & Step-by-Step Answer:
Length of the rectangle = (8x + 5) cm Breadth of the rectangle = (5x + 3) cm ∴ Area of the rectangle = length × breadth = (8x + 5) × (5x + 3) = 8x × (5x + 3) + 5 × (5x + 3) = (8x × 5x) + (8x × 3) + (5 × 5x) + (5 × 3) = 40x² + 24x + 25x + 15 = 40x² + 49x + 15 ∴ The area of the rectangle is (40x² + 49x + 15) sq. cm.