1: =>x-7=0
=>x=7
2: =>x-4=0
=>x=4
3: =>2x-6=0
=>x=3
4: =>3x-12=0
=>x=4
5: =>5x-15=0
=>x=3
6: =>4x-24=0
=>x=6
7: =>6x-12=0
=>x=2
8: =>15x-45=0
=>x=3
9: =>17x-34=0
=>x=2
10: =>9x-27=0
=>x=3
11: =>15-x=5
=>x=10
12: =>24-x=23
=>x=1
13: =>2x-27=25
=>2x=52
=>x=26