Question

Find the roots of the quadratic equation x^2 – 8x = 9 by completing the square. Show your work.

Answer 1

x = -1

x = 9

Explanation:

First you have to equals the equation to zero, then you have to find two numbers that their sum equals 8 and multiplied equals -9. In this case, those numbers are -1 and 9.

`x^2-8x=9\\x^2-8x-9=0\\(x+1)(x-9)=0\\`

After you find those numbers, you split the equation and equals each term to zero.

`(x+1)=0, x=-1\\(x-9)=0, x=9\\`

So the answer is x=-1 and x=9

Hope you understand!