Answer
20°, 30°, 130°
Work Step by Step
1. Internal angles of a triangle have a sum of 180°
(x+15)+(x+5)+(10x-20)= 180
2. Solve the equation for x
x+10x+x=180-15-5+20
12x=180
x=15$^{\circ}$
3. Then find angles by replacing x=50
(15)+15=30$^{\circ}$
(15)+5=20$^{\circ}$
10(15)-20=130$^{\circ}$
