Answer:
x = 3.5
Explanation:
Since the triangles are similar we can use ratios to solve
4 7
------ = ------
(4+2) ( 7+x)
Using cross products
4(7+x) = 7*(4+2)
Distribute
28+4x = 42
Subtract 28 from each side
4x = 42-28
4x= 14
Divide by 4
4x/4 = 14/4
x = 7/2