Start with the equation: 11y + 7y = 180 because those two angles are supplementary. Solving that will give you that y = 10.
The angle that is labelled 7y is therefore 70 degrees. We can write the following equation will the 5x because it is corresponding to the 70 degree angle.
5z = 70 z = 14
And we can also write and solve for the x, using the 70 degree angle. 70 + 10x = 180 10x = 110 x = 11
