One number is 8 more than twice another. If their product is 640, find the answers

There are 2 answers

1. smaller number is - 32, bigger number is - 20

2. smaller number is 16, bigger number is 40

Step-by-step explanation:

Let x be the smaller number.

x (2x+8) = 640

expand

2x²+8x=640

move 640 to the other side and divide everything by 2

2x²+8x-640=0

x²+4x-320=0

use quadratic formulas to expand then group

x²+20x-16x-320=0

x (x+20) - 16 (x+20)

(x+20) (x-16)

x=-20

x=16

to find the bigger/smaller numbers, use 2x+8

2*-20+8 = - 32

2*16+8 = 40