6X-7=8
6X=7+8
6X÷6=15÷6
X=2,5
2X-11=7X+4
2X-7X=4+11
-5X÷-5=15÷-5
X=-3
6-3X=15+4X
-3X-4X=15-6
-7X=9
-7X÷-7=9÷-7
X=-9/7
