Answer:
y = 54
Step-by-step explanation:
Two of the sides are congruent, so the angles that are facing the two sides are also congruent, so:
3(x + 7) = 63
3x + 21 = 63
3x = 42
x = 14
A triangle equals 180 degrees, and input 14 into the equation, so:
3(14 + 7) + 63 + y = 180
3(21) + 63 + y = 180
63 + 63 + y = 180
126 + y = 180
y = 54
