Answer:
x = 90
Step-by-step explanation:
If lines A and B were parallel , then
∠ 1 and ∠ 4 are corresponding angles and congruent, so
3x - 160 = x + 20 ( subtract x from both sides )
2x - 160 = 20 ( add 160 to both sides )
2x = 180 ( divide both sides by 2 )
x = 90
