Answer:
a or d im very positive that is d
Step-by-step explanation:
Fifteen thousand six-hundred and thirty-eight
You are correct. The answer is choice C.
The other choices A, B, D have each side add up to 180 degrees either because the angles are a linear pair (adjacent and supplementary) or because the angles are same side interior angles. Same side interior angles are supplementary if a transversal line cuts through a pair of parallel lines as so happens in this diagram.
For me personally, the easiest way to do this is by isolating the x² term, and finding the square root of both sides. The hardest way (well actually, the longest way) would be to use the quadratic formula. It just complicates things unnecessarily.