Can somebody help me with more line segment problems?

Now I am not sure what length you're supposed to find for problem 9, but x = 3.3 i think.

10.)

(14+x)+(x+21) = 13

2x+35=13

2x = -22

x = -11

FE = -11 + 14 = 3 units

11.)

10 + 2x - 10 = 3x - 8

2x = 3x - 8

-x = -8

x = 8

10 + 2(8) -10 = 16 units

to determine the unit cost your would divide the total cost by the number sold.

7 bagels for $4.41       $4.41/7 = $.63 each at fresh side

5 bagels for $3.60         $3.60/5 = $.72 each at value mart