Answer:
MN = 50
Explanation:
You want the length of the base segment MN in triangle MNO, where MN is marked 41+3x and parallel midsegment PQ is marked 49-8x.
Midsegment
The midsegment is half the length of the parallel base segment. That means the base segment is double the length of the midsegment:
MN = 2·PQ
41 +3x = 2(49 -8x)
41 +3x = 98 -16x
19x = 57 . . . . . . . . add 16x-41
x = 3
MN = 41 +3x = 41 +3·3 = 50
The length of MN is 50 units.