How do you solve quadratics by taking square roots ?

Start with the equation

Factor from the first two terms:

Complete the square; do this by adding an appropriate constant to to form a perfect square trinomial. Recall that

So here we have

and we have to add to make the perfect square. But we also have to subtract this same constant to preserve equality:

Now we can take the square root and solve for :

You should recognize this formula...

answer: 1,380

step-by-step explanation:

1: you turn %15 into a decimal by moving the decimal point two places to the left.

2: and then you multiply .15 by 1,200 , which will get you 180.00

3: from there you will add 180 to 1,200

4: which will get you 1,380

hope it *im kind of slow so idk if my answer is right*