Answer:
40
Step-by-step explanation:
Sum of all angles of triangle = 180°
∠W + ∠X + ∠Y = 180
10x + 17 + 2x - 9 + 3x + 7 = 180
10x + 2x +3x + 17 - 9 + 7 = 180
Combine like terms
15x + 15 = 180
15x = 180- 15
15x = 165
x = 165/15
x = 11
∠Y = 3x +7 = 3*11 + 7 = 33 + 7 = 40
