The quadratic -6x^2+72x+216 can be written in the form a(x+b)^2+c, where a, b, and c are constants. What is a+b+c?
+128474 -6x^2 + 72x + 216 ...... factor out the -6
-6 ( x^2 - 12x - 36)
Take 1/2 of 12 = 6....square it = 36......add and subtract it within the parentheses
-6 ( x^2 - 12x + 36 - 36 -36 ) factor the first three terms and simplify the rest
-6 [ ( x - 6)^2 - 72 ] distribute the -6 across the terms in the brackets
-6(x - 6)^2 + 252
a = -6 b = -6 c = 252
And their sum = 240
