We know that a supplementary angle is 180 degrees because they add up to 180 degrees.
To solve for x:
Add the whole numbers
7x + 33 + 70 = 180
Subtract 103 on both sides.
7x + 103 = 180
-103 -103
Divide 7 on both sides to get x alone.
7x = 77
--- ---
7 7
x = 11
Check:
7(11) + 33 + 70 = 180
77 + 33 + 70 = 180
110 + 70 = 180
180 = 180
The angle
7(11) + 33
77 + 33
equals to
110
Which means that the angle is 110 degrees.