9514 1404 393
Answer:
 x = 22
Explanation:
When lines l and m are parallel, the marked angles are supplementary.
 (2x -3)° +(6x +7)° = 180°
 8x +4 = 180 . . . . . . . . . . . divide by °, collect terms
 8x = 176 . . . . . . . . . . subtract 4
 x = 22 . . . . . . . . divide by 8