Answer:
x+7
Step-by-step explanation:
So it's been a while since I took Geometry, so I don't know what principle makes these angles equal to each other, but I know that they are in fact equal. So that means that 6x +3 = 45. Subtract 3 from each side gets you 42+6x, then divide each side by 6, which gets you your answer of x=7.
