9514 1404 393
Answer:
x = 220
Step-by-step explanation:
Consecutive interior angles are supplementary:
1/4x +3 + 1/2x +12 = 180
3/4x +15 = 180 . . . . . . . . . . . collect terms
3/4x = 165 . . . . . . . . . . subtract 15
x = (4/3)165 . . . . . multiply by 4/3
x = 220
