Answer:
x = 20
Step-by-step explanation:
Since m and n are parallel lines then
5x + 30 and 3x - 10 are same side interior angles and are supplementary, thus
5x + 30 + 3x - 10 = 180
8x + 20 = 180 ( subtract 20 from both sides )
8x = 160 ( divide both sides by 8 )
x = 20
