Two sevenths X+ one third X= 13.

Solution: thirteen in twenty X= 13.

X= 13÷ 13/2 1

X=2 1

(3 1/2 1= XIII, XXI)

The second one:

4.5X+X= 1 1/ 17

Solution: 5.5x =1117.

x = 1 1/ 17÷ 1 1/2

X=2/ 17

The third one:

19/20X=7/ 10+2/5

Solution19/20x =17/10.

x = 10/ 17 \ 19/20

x = 10/ 17×20/ 19

X=22/ 19

Complete the desired solution.