2 1/4 - 1 3/19 = 9/4 - 22/19 = 171 /76 - 88/76 = 83/76 = 1 7/76
1.69,44:32=21,7;
2.128340:138=930;
3.3200:128=25;
<span>5/7* (21/20-7/30)-16/21:8/7= -1/12
1) 21/20-7/30=63/60-14/60=49/60
2) 16/21:8/7=16/21</span>·7/8=2/3
3) 5/7·49/60=7/12
4) 7/12-2/3=7/12-8/12= -1/12
1)
6х+8х-7х=714
7х=714
х=714÷7
х=102
2)
23х-19х+5х=1827
9х=1827
х=1827÷9
х=203