Removing Common Factor How do I factor this -4x^2+12x-16

aruv | Student

`-4x^2+12x-16=-4(x^2-3x+4)`

since

`x^2-3x+4=0`

`x=(3+-sqrt(9-14))/2=(3+-isqrt(7))/2`

Therefore

`-4x^2+12x-16=-4(x-(3+isqrt(7))/2)(x-(3-isqrt(7))/2)`