Answer:
c = 36
Step-by-step explanation:
x^2 + 12x
Take the coefficient of x
12
divide by 2
12/2 =6
square it
6^2 = 36
Add this
c=36
c =36
a perfect square (ax+b)² expanded will become ax² + 2ab + b²
since a is one (x² = 1*x²), 2b = 12, and b = 6
c = b²
c = 6²
