Inactive Tutor answered 07/11/16
Tutor
New to Wyzant
There is a way to do this, but it requires you to find the solutions when you set this trinomial equal to zero.
x2 + 16x + 7 = 0
Use quadratic formula:
x = (-b ± √(b2 - 4ac)) / 2a
where:
a = 1
b = 16
c = 7
Plugging in the values,
x = (-16 ± √(256 - 28)) / 2
x = (-16 ± √228) / 2
x = (-16 ± √4√57) / 2
x = (-16 ± 2√57) / 2
x = -8 ± √57
x = -8 - √57 and x = -8 + √57
We use this fact to factor.
x2 + 16x + 7 = (x + 8 + √57)(x + 8 - √57)