3х-х=13-9 2х=4 х=4/2 х=2 5х+3х-3=6х+11 5х+3х-6х=11+3 2х=14 х=14/2 х=7
3x+9=13+x 3x-x=-9+13 2x=4 X=4:2 X=2 5x+3(x-1)=6x+11 5x+3x-3=6x+11 5x+3x-6x=3+11 2x=14 X=14:2 X=7