The answer is about 13.9927.
You would divide 52/11 and then subtract that decimal by 18.65.
18.65-4.7272=13.9927.
Before you use the quadratic formula, you have to make sure the equation itself is a quadratic and that a and b are not 0.
I think the answer is... it is true
Remember
difference of 2 perfect squares
a^2-b^2=(a-b)(a+b)
(x)^2-(7)^2=(x-7)(x+7)
set to zero
x-7=0
x=7
x+7=0
x=-7
x=-7 or 7
I think it is 47 not sure