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?
+2668 Note that (x+b)2=x2+b2+2xb
This means that a=−6
Also, note that −6×2xb=72x, because it is the only term with x.
This means b=−6
Expanding what we have gives us: −6x2+72x−216, so we add 432, to make the constant positive.
This means a+b+c=420
+2668 Note that (x+b)2=x2+b2+2xb
This means that a=−6
Also, note that −6×2xb=72x, because it is the only term with x.
This means b=−6
Expanding what we have gives us: −6x2+72x−216, so we add 432, to make the constant positive.
This means a+b+c=420
