Answer:
x = 18
Explanation:
The line joining 2 midpoints of the non parallel sides of a trapezoid is 1/2 the sum of the two parallel lines.
Put in much simpler language XY = 1/2 (BC + AD)
4x - 2 = 1/2 (6x + 1 + x) Combine the right
4x - 2 = 1/2 (7x + 1) Multiply by 2
8x - 4 = 7x + 1 Add 4 to both sides
8x = 7x + 5 Subtract 7x
x = 5
But what you want is the length of XY
XY = 4x - 2 = 4*5 - 2 = 18
Sorry I noticed too late that I used x for s. The answer would still be 18.