Task/26339376
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t₁ =45 минут = 45/60 ч = 3/4 ч
t₂ = 40 минут = 40/60 ч = 2/3 ч
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V =S / t₁ =S / (3/4) = 4S / 3 .
С другой стороны :
S = (V+10)*t₂ = (V +10)*2/3 =(4S /3 +10)*2/3 = 8S / 9 +20 / 3 .
S = 8S / 9 +20 / 3 || * 9
9S = 8S + 60 ;
S =60 (км) .
ответ : 60 км .
24*0.2=4.8
6*4.8=28.8
2*6.7=13.4
4.8-28.8=-24
-24+13.4=-10.6
2)
-3целых 5/12+1целое 11/18=-41/12+29/18=-123/36+58/36=-65/36
3.6+11.5=15.1
-1 целая 7/8*1 целую 1/3=-15/8*4/3=-5/2=-2.5
-135.2:-6.5=20.8
2(m+1)^2+3(m+2)^2=2(m^2+2m+1)+3(m^2+4m+4)=2m^2+4m+2+3m^2+12m+12=5m^2+16m+14
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