Peter H. answered • 05/19/14

Tutor

New to Wyzant
Tutoring in Math, Science, and Computer Engineering

Hi Sam,

With the square root method, we need to get the equation in the form of

something squared = something else

and then take the square root of each side.

So, first let's divide each side of your equation by 3, to get

(x-4)^2 = 25

Now we can take the square root of each side, and get

(x-4) = 5 and (x-4) = -5

Remember, 5*5=25, but also -5 * -5 = 25, so taking the square root gives us two solutions. Now we solve each of our equations

(x-4) = 5 --> x = 9

(x-4) = -5 --> x = -1

Our two answers are thus x=9 and x=-1. I leave it to you to insert these values back into the original equation and make sure I got it ok! Always double check your work.