Add 799.99 and 679.99 which equals 1479.98
Then divide 1479.98 by 2 which equals 739.99
Your answer is c. 739.99
This is a perfect square trnomial
(a+b)²=a²+2ab+b²
we see that a=5x and b=2
(5x)²+2(5x)(2)+2²=0
factor
(5x+2)²=0
set equal to zero
5x+2=0
5x=-2
x=-2/5
