solve similar triangles (advanced)

Answer:
Step-by-step explanation:
The two triangles given that are similar are
EDA and CBA
From this one fact, we get the following proportion.
ED/CB = (x + 8) / x Substitute for the line lengths
13/7 = (x + 8)/x Cross Multiply
13x = 7(x + 8) Remove the brackets
13x = 7x + 56 Subtract 7x from both sides
13x - 7x = 56
6x = 56 Divide both sides by 6
x = 56/6
x = 9.33
Answer:
x = 9 1/3
Step-by-step explanation:
If we draw line CG that is parallel to AD so it intersects DE at G, it will divide segment DE into DG = 7 units and GE = 6 units. The resulting triangle CGE is similar to triangle ABC. Of course, CG = BD = 8.
AB/CG = CG/GE
x/7 = 8/6
x = 7(8/6) = 7(4/3) = 28/3 . . . . multiply by 7 and reduce the fraction
x = 9 1/3