To solve this problem you must apply a theorem called: Intersecting secant theorem. The proccedure is shown below:
1) For the figure shown on the left:
(5)(x+5)=(6)(4+6)
5x+25=60
5x=60-25
x=35/5
x=7
2) For the figure shown on the right:
(3)(3+5)=(4)(x+4)
24=4x+16
24-16=4x
8=4x
8/4=x
x=2