Question

How do you solve `x^2+2x-7=17` by completing the square?

Answer 1

Take `-7` to the right:
`x^2+2x=17+7`
`x^2+2x=24`
add and subtract `1` to the left:
`x^2+2x+1-1=24`
`(x^2+2x+1)-1=24`
`(x+1)^2-1=24`
`(x+1)^2=25` take the square root of both sides and get rid of the `()^2`:
`x+1=+-sqrt(25)`
`x=-1+-5`
So you get:
`x_1=-1+5=4`
`x_2=-1-5=-6`