Х+3=11,х+7=19,х-8=5,х-9=4,60-х=59,12-х=12
X+3=11 X=11-3 X=8; X+7=19 X=19-7 X=12; X-8=5 X=5+8 X=13; X-9=4 X=4+9 X=13
1) 8. 2)12. 3)13. 4)13. 5)1. 6) 0.