SOLUTION: Help!! Solve. let f(x) = (x + 10)^2. Find x so that f(x) = 72

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Help!! Solve. let f(x) = (x + 10)^2. Find x so that f(x) = 72       Log On


   

Question 298409: Help!!
Solve.
let f(x) = (x + 10)^2. Find x so that f(x) = 72
Answer by chibisan(131) About Me  (Show Source):
You can put this solution on YOUR website!
Combine both functions together,
(x + 10)^2 = 72
x + 10 = +- sqrt(72)
x = +- sqrt(72) - 10
x = -1.51 , -18.5 ( 3 significant figures.)