<span>а)5*(у-1)-3*(у-2)=7-у+3</span>
<span>5y-5-3y+6+7-y+3</span>
<span>5y-3y+y=7+3+5-6</span>
<span>3y=9</span>
<span>y=3</span>
проверка:
15-9+3=7+3+5-6
<span>15-9+3=9</span>
<span>9=9</span>
<span>б)<span>9*(х-5)+4*(6-х)=3+3*(х+20)-2х</span></span>
<span><span> 9x-45+24-4x</span></span>
<span><span> =3+60+45-24</span></span>
<span><span> 4x=84</span></span>
<span><span> x=21</span></span>
<span><span> проверка</span></span>
<span><span> </span></span><span>9x-4x-3x+2x</span><span>=3+3x+60-2x</span>
<span> 189-84-63+42=84</span>
<span> 84=84</span>
<span> </span>