Since the lines u and v are parallel, this means that the angles (10x - 5) = (7x + 4)
and that 7x + 4 + y = 180.
You can solve the first equation for x, then substitute that value into the second equation and rearrange for y.
10x - 5 = 7x +4
3x -5 = 4
3x = 9
x = 3°
∴ 7(3) + 4 + y = 180
25 + y = 180
∴ y = 180 - 25
y = 155°
