Answer:
7
Step-by-step explanation:
Triangles add up to 180.
90 degrees are already used, leaving us with 90.
90 = 7x + 6 + 4x + 7
Combine like terms.
90 = 11x + 13.
Subtract.
90 - 13 = 77 = 11x
Divide.
77 / 11 = 7.
7 = x
