Ответ:
1)а)2/7+1/3=13/21;б)2.6-4.5=-1.9=19/10
<span>x+(90+30)=180
</span><span>x+120=180
х=180-120
х=60
</span><span>(x+60)*5=500
х+60=500/5
х+60=100
х=100-60
х=40
</span><span>(x+90)+30=180
</span><span>x+90+30=180
х+120=180
х=180-120
х=60
</span><span>5*x+300=500
5х=500-300
5х=200
х=200/5
х=40</span>
22792/7=3 256
3256х16=52 096
Ответ 52.096