Question

how do you find this

Answer 1

mid segment 

2x - 9 = 10/2
2x - 9 = 5
2x = 14
x = 7

Answer 2

warning this is probably wrong!
2x-9 looks like it is half of the 10 units long line
so 10/2=5 
2x-9=5
2x-9(+9)=5(+9)
2x=14
2x(/2)=14(/2)
x=7
so if its wrong please don't get made