Question

How do you solve `3x^2 - 12x + 5=0` by completing the square?

Answer 1

Write it as:
`x^2-12/3x=-5/3`
`x^2-4x=-5/3` add and subtract 4
`x^2-4x+4-4=-5/3`
`(x-2)^2-4=-5/3`
`(x-2)^2=4-5/3`
`(x-2)^2=7/3`
`x-2=+-sqrt(7/3)`
Finally:
`x_(1,2)=2+-sqrt(7/3)`