The answer to that question is 15.51
Answer:
x + 7
Step-by-step explanation:
x2 + 4x − 21
set equal to 0
x2 + 4x − 21 = 0
factor
(x - 3) (x + 7)
x2 + 11x + 28
set equal to 0
x2 + 11x + 28 = 0
factor
(x + 4) (x + 7)
0 = x + 2 + x^2
x^2 + x + 2 = 0
a = 1, b = 1, c = 2
discriminant = b^2 - 4ac = 1^2 - (4 x 1 x 2) = 1 - 8 = -7
