Answer:
x=7
Explanation:
We can use similar triangles and proportions to solve. Put the sides of the smaller triangle over the sides of the larger triangle.
5 3
----------- = -------------
40 +5 3 + (2x+10)
Simplify
5 3
----------- = -------------
45 (2x+13)
Cross multiply
5 *(2x+13) = 3*45
Divide by 5
5/5 *(2x+13) = 3*45/5
2x+13 = 3*9
2x+13 = 27
Subtract 13 from each side
2x+13-13 = 27-13
2x= 14
Divide by 2
2x/2 =14/2
x=7