Question

What is the product of 5x + 3 and 8x2 – 2x + 5? A) 40x3 + 14x2 – 19x – 15 B) 40x3 + 14x2 – 31x – 15 C) 40x3 + 34x2 + 31x + 15 D) 40x3 + 14x2 + 19x + 15

Answer 1

Answer: D: 40x3 +14x2+19x+15

Explanation:

(5x + 3) (8x2 - 2x + 5)

5x ( 8x2 - 2x + 5) +3 ( 8x2 - 2x + 5)

expanding the bracket

(40x3 - 10x2 + 25x) + ( 24x2 - 6x +15)

removing the bracket

40x3 - 10x2 + 25x + 24x2 - 6x + 15

collecting like terms

40x3 - 10x2 + 24x2 + 25x - 6x + 15

40x3 + 14x2 +19x + 15

Answer 2

D is the answer

Explanation: