Question

What substitution should be used to rewrite 6(x + 5)2 + 5(x + 5) – 4 = 0 as a quadratic equation?
u = (x + 5)
u = (x – 5)
u = (x + 5)2
u = (x – 5)2

Answer 1

u = (x + 5)

Then let u = x + 5 to get 6u^2 + 5u - 4 = 0, a quadratic in u.