How do you solve x plus 9 equals x squared?

Answer 1

By factorising:
x + 9 = x2
x2 - x - 9 = 0
(x - 3.54)(x + 2.54) = 0

x = 3.54, x = -2.54

By the quadratic formula:
x = -(-1) ± √[(-1)2 - 4(1)(-9)]/2(1)
x = 1 ± √(1 - -36)/2
x = 1 ± √37/2
x = 0.5 ± 6.08/2

x = 0.5 + 3.04 = 3.54, x = 0.5 - 3.04 = -2.54

The same solutions are given both ways, which confirms the result.