How do you solve u=sqrt(-u+12)?

1 Answer
Aug 29, 2017

u = - 4 or u = 3

Explanation:

Follow these simple steps

u = sqrt (-u + 12)

Square both sides

u^2 = sqrt (-u + 12)^2

u^2 = -u + 12

Collect like terms

u^2 + u - 12 = 0 -> Quadratic

Solving the Equation we have +4 , -3 as the quadratic factors

u^2 + 4u - 3u - 12 = 0

(u^2 + 4u) (- 3u - 12) = 0

u(u + 4) -3 (u + 4) = 0

(u + 4) (u -3) = 0

(u + 4) = 0 or (u -3) = 0

u = - 4 or u = 3