i'm gonna assume that you were talking about triangle problem :0
Explanation:
Triangle: all (three) angles add up to 180 degrees. Always.
Given angles: 76 degrees and 63 degrees.
x must be the degree of an unknown angle that has to be solved.
76 + 63 = 133 degrees
Now subtract 133 degrees from 180 degrees to find the unknown angle.
180 - 133 = 47 degrees = x
ANSWER: x = 47 degrees