Question

How do you solve the quadratic equation by completing the square: `x^2-12x+20=0`?

Answer 1

I found:
`x_1=10`
`x_2=2`

Explanation:

Rearrange your equation:
`x^2-12x=-20`
add and subtract `36`;
`x^2-12xcolor(red)(+36-36)=-20`
`x^2-12x+36=-20+36`
so you can write:
`color(blue)((x-6)^2=16)`
square root both sides:
`x-6=+-sqrt(16)=+-4`
so you end up with two solutions:
`x_1=6+4=10`
`x_2=6-4=2`