Alright...so the coordinates of an ordered pair have opposite signs [one sign is positive while the other is negative] so we could have an example of (-x,+y) or (+x,-y) ...that means out of the 4 quadrants these points could be in the 2nd quadrant or the 4th quadrant or corners of the graph
The answer would be 54 medium T-shirts out of the 126 on the rack
(3x + 5)° + (10x - 7)° = 180°
13x + (-2) = 180
13x = 180 + 2
13x = 182
x = 14
∠QRT = 3 * 14 + 5 = 42 + 5 = 47°
∠TRS = 10 * 14 - 7 = 140 - 7 = 133°