Question

What is the answer to x^{2}-2x=15

Answer 1

Two solutions:

x = 5 and x = -3

Explanation:

Simplify:

x^{2} - 2x = 15

-15 -15

x^{2} - 2x -15 = 0

Find what numbers multiplied by eachother equal -15 and also add to -2:

-5 * 3 = -15

-5 + 3 = -2

Rewrite equation and put each expression equal to 0:

(x - 5)(x + 3) = 0

x - 5 = 0 x + 3 = 0

+5 +5 -3 -3

x = 5 x = -3