In a triangle, the line joining the midpoints of two sides is parallel to the third side and equal to half its length
From the given figure we can see triangle VUW
Since Y is the midpoint of VW
Since Z is the midpoint of VU
Then by using the rule up, ZY joining the midpoints of VW and VU
Since UW is the third side in the triangle, then

Since ZY = (x + 20)
Since UW = (x + 28), then

Multiply both sides by 2

The equation is 2(x + 20) = (x + 28)
The answer is D