9х+12-3х-8=(9-3)*х+12-8=6*х+4
34+(9х-17)-4х=34+9х-17-4х=(9-4)*х+34-14=5*х+20
1)100-90=10
2)100*2=200
3)9000:10:200=900:200=
1) 6×70=420
2)1200:40=30
3)420+30=450
4)565-450=115 вот всё легко
18(x-17) = 108
18x - 18*17 = 108
18x - 306 = 108
18x = 108 + 306
18x = 414
x = 414 : 18 = 23
Ответ: 23
1)2/9+7/11-10/99=(2*11+(7*9)-10))/99=
=(22+63-10)/99=75/99=25/33