Answer:
Explanation:
If the two triangles are similar then you need to set up a proportion.
Segment ED is similar to GD
and DF is similar to DC
So.
48/(5x-2)=40/(2x+7)
Cross multiply
48(2x+7)=40(5x-2) (if you see it you can reduce numbers so its not so big but i won't to keep things simple)
96x+336= 200x-80
416=104x
x=4