Solve x^2−6x=90 using completing the square. Answer the questions below.

Question

Solve  using completing the square. Answer the questions below.

a) To make the left side of the equation a perfect square, we need to add _________ on both sides.

b) Turn the left side of the equation into a perfect square. Once you have the perfect square on the left side, the equation will look like ______________

 (Enter your equation in the form: a binomial squared equals a constant)

c) The solution to the given equation is

(Don't approximate your solutions, and separate multiple solutions by a comma)

Answer 1

Hi Jamie

You can find the steps for the completing the square on the internet or in your text check them out briefly they are as follows

1. Make sure the coefficient x² is 1
2. Move everything over to the left side of the equation except the constant
3. Take half the coefficient of x in your case -6, half is (-6/2) and square it
4. Rewrite the left side of the equation as a perfect binomial square
5. Eliminate the exponent
6. Solve for x

a. (-6/2)² = (-3)² = 9

x² -6x + 9 = 90 + 9

b. (x - 3)² = 99

You have a bit more work to do below give it a try

c.x = -√99 + 3; x = +√99 + 3

I hope this helps