What are the solutions to the equation? x2 + 6x = 40

a. x = −10 and x = 4
b. x = −8 and x = 5
c. x = −5 and x = 8
d. x = −4 and x = 10

Just plug in the numbers:

4:  16 + 24 = 40  YES

5 = 25 + 40 ≠ 40 NO

8: 64 + 48 ≠ 40 NO

10: 100 + 60 ≠ 40 NO

So A. is the correct answer. Just to be sure:

-10: 100 + ( - 60) = 40 

Your answer is A. Hope that helps! :) 

Ithink the answer is d.