1)∠VWU=180°-(4x-15°)
∠VWU=180°-(x+20°+x+25°)
180°-(4x-15°)=180°-(2x+45°)
-4x+2x=-15°-45°
2x=60°
x=30° ∠VWU=180°-(4×30°-15°)=75°
2)∠ACB=180°-(3x+20°)
∠ACB=180°-(2x-40°+2x+20°)
180°-(3x+20°)=180°-(4x-20°)
-4x+20°=-3x-20°
x=40° ∠ACX=3×40°+20°=140°
3)∠TVU=180°-(x+35°)
∠TVU=180°-(x+15°+2x-70°)
180°-(x+35°)=180°-(3x-55°)
2x=90°
x=45° ∠TVX=45°+35°=80°