The quadratic $-6x^2+36x+216$ can be written in the form $a(x+b)^2+c$, where $a$, $b$, and $c$ are constants. What is $a+b+c$?

-47

Step-by-step explanation:

Step 1: Factor GCF

-6(x² - 6x - 36) = 0

Step 2: Divide by -6 on both sides

x² - 6x - 36 = 0

Step 3: Isolate x's

x² - 6x = 36

Step 4: Complete the Square

x² - 6x + 9 = 36 + 9

(x - 3)² = 45

Step 5: Move everything to one side

(x - 3)² - 45 = 0

So, a = 1, b = -3, c = -45

1 - 3 - 45 = -47

the answer is 62.8 cubic units