x2 + 13x + 36 = 0
36 + 13x + x2 = 0
(9 + x)(4 + x) = 0
9 + -9 = 0
0 + x = 0 + -9
x = 0 + -9
x^2 - 13x + 36 =
(x - 9)(x - 4) = 0
4² - 13(4) + 36 = 0
16 - 52 + 36 = 0
-36 + 36 = 0
0 = 0
9² - 13(9) + 36 = 0
81 - 117 + 36 = 0
-36 + 36 = 0
0 = 0
So the Answer Is x = 9 , 4