9/10*8=9*8/10=72/10=7 целых 2/10=7 1/5
<span>12-7(x-4)=3x+4
12-7х+28=3х+4
-7х-3х=-40+4
-10х=-36
х=-36:(-10)
х=3,6
</span>
1) 1.7y=1.53
y=1.53/1.7
y=0.9
2)4.2*(0.25×x)=1.47
1.05x=1.47
x=1.47/1.05
x=1.4
а)32,4:(7,06х-101,2)*1,8=1,458
32,4*1,8=1,458(7,06х-101,2)
58,32=10,29348х-147,5496
58,32+147,5496=10,29348х
205,8696=10,29348х
х=205,8696:10,29348
х=20
б)(0,85х-1,72):1,3=2,6
0,85х-1,72=2,6*1,3
0,85х=3,38+1,72
0,85х=5,1
х=5,1:0,85
х=6