
Isidro L. answered 03/28/19
AP Calculus AB /Algebra Teacher 20 years Experience.
This problem is about finding "c" in the quadratic expression: ax^2 +bx +c=0
In order to find "c" we need to use the following formula C= (-b/2)^2.
If you notice in the above expression a=1, b=-16 and c=? is unknown.
Let apply the formula: C= (-(-16/2))^2 = (8)^2=64
Now we are going to substitute C to complete the expressions ax^2+bx+c=0
ax^2 +bx +c=0 , x^2 -16x +64=0, so the constant term is c=64
To check the answer , we can see that the new expression is a perfect trinomial.
x^2 -16x+64=0
Factoring (x-8)(x-8)=0 . or (x-8)^2 . therefore the answer is c=64.