Answer is x = (0) zero
Angles around a point will always add up to 360 degrees, so the three angles will add up to 360x
x + 138
x + 50
172
So if we use 0 for x, we have
138 + 50 + 172 which equals 360
So m ∠ QST: 0 + 138 = 138
So m ∠ RSQ: 0 + 50 = 50
And m ∠ RST = 172
Problem solved!
