Answer:
40
Step-by-step explanation:
3x + 7 = 5x - 15
2x = 22
x = 11
QC = 51 - x = 51 - 11 = 40
The supplement to ∠1 = 180°-135° = 45° = ∠3, so m is parallel to j and l.
∠2 ≠ 45° and ∠2 ≠ 135°, so k is not parallel to j, l, or m.
?
D