156 and (14y+30) are opposite angles so they are the same. You can use this information to put them into an equation to solve;
14y+30 = 156
You want you the the y's alone, so you subtract 30 from each side.
14y = 126
Then divide each side by 14 to get what just 1 y is.
y = 9
Then to find what the other pair of opposite angle add up to subtract 156x2 from 360
156x2 = 312 360-312 = 48
Halve 48 to get the sum of just one of the opposite angles
48/2 = 24
Now you know that 3x = 24. Solve this equation
x = 8
