Question

Solve x2 + 10x = -21.

x = 7 and x = 3
x = -7 and x = -3
x = -7 and x = 3
x = 7 and x = -3

Answer 1

the 2nd one

Explanation:

Answer 2

answer is x = -7 and x = -3

x2 + 10x = -21
x2 + 10x + 21 = 0
(x +3) (x +7) = 0

(x +3) = 0
and
(x + 7) = 0
so x = - 3 and x = -7