c is 36.
a perfect square trinomial, (x + y)² = x² + 2xy + y²
so, if we have the x of the 12x, what is left is the 12
since we also have the 2 (used for every square trinomial), 12/2 = 6
since c is the squared value, we do 6² = 36
hope it helps :)
Answer:
x2 + 2 (6) + 62 = (x + 6)2 a perfect square. Therefore c = 36
