C=пD 1)40 *3,1=124 (см)-понадобится
59/9+3-7/12=
(59*4+3*36-7*3)/36=
(236+108-21)/36=323/36=
8 35/36
1) <span>5(2у-9)+6у=4(3у-2)-21
10у-45+6у= 12у-8-21
16у-45=12у-29
16у-12у= 45-29
4у= 16
у= 16:4
у= 4
2)</span><span>5у+7(3-у)=3(5-2у)-6
5у+21-7у=15-6у-6
-2у+21=9-6у
6у-2у=9-21
4у= -12
у= -12:4
у=-3
3)</span><span>7у-4(3у+5)=2-3(4у-9)
7у-12у-20= 2-12у+27
-5у-20= 29-12у
12у-5у= 20+29
7у= 49
у= 49:7
у= 7</span>
Для12-х=6 15-х=9х+7=12 12-х=7 4+х=11 х+4=11 11-х=4х+5=9 15-х=11<span>11-х=8 х+5=8</span>