The quadratic 3x^2-24x+72 can be written in the form a(x+b)^2+c, where a, b, and c are constants. What is a+b+c?
3x^2-24x+72 re-arrange
3 (x^2 -8x) + 72 complete the square for 'x'
3 ( x-4)^2 -48 + 72
3 (x-4)^2 +24 now add a b c