Factor completely. 640-10x^2

10 (8-x) (8+x)

Step-by-step explanation:

640-10x^2

Factor out 10

10 (64 - x^2)

Notice that inside the parentheses is the difference of squares

10 (8^2 - x^2) and a^2 - b^2 = (a-b) (a+b)

10 (8-x) (8+x)

10 (8 - x) (8 + x)

Step-by-step explanation:

Given

640 - 10x^2

Solution

Take out 10 on each side of the minus sign

10 (64 - x^2)

The expression in the brackets is a difference of squares which factors as

a^2 - b^2 = (a + b) (a - b)

Factor the expression inside the brackets as a difference of squares.

64 = 8*8

x^2 = x*x

10 (8 - x) (8 + x)