Question

How do you solve using completing the square method `x^2+2x=9`?

Answer 1

`x = - 1 +- sqrt10`

Explanation:

`x^2 + 2x = 9`
`x^2 + 2x + 1 = 9 + 1`
`(x + 1)^2 = 10`
Take the square root of both sides:
`x + 1 = +- sqrt10`
The 2 real roots are:
`x1 = - 1 + sqrt10`
`x2 = -1 - sqrt10`