3х+2у=35
х+3у=35 (умножаем на -3)
3х+2у=35
-3х-9у=-105
1) -7у=-70
у=10
2) 3х+20=35
3х=15
х=5
Овтет: (5;10)
3x-15-2x-8= -5x+1; 3x-2x+5x=1+8+15; 6x=24; x=24:6; x=4. Ответ: x=4.
<span><span><span>
18−<span>5<span>(<span>+3</span>)</span></span></span>><span>1−<span>7</span></span></span><span><span>18−<span>5<span>(<span>x+3</span>)</span></span></span>><span>1−<span>7x</span></span></span></span><span><span><span><span>18−<span>5</span></span>−15</span>><span>1−<span>7</span></span></span><span><span><span>18−<span>5x</span></span>−15</span>><span>1−<span>7x</span></span></span></span><span><span><span>3−<span>5</span></span>><span>1−<span>7</span></span></span><span><span>3−<span>5x</span></span>><span>1−<span>7x</span></span></span></span><span><span><span><span><span>−5</span></span>+<span>7</span></span>><span>1−3</span></span><span><span><span><span>−5</span>x</span>+<span>7x</span></span>><span>1−3</span></span></span><span><span><span>2</span>><span>−2</span></span><span><span>2x</span>><span>−2</span></span></span>x> - 1 <span><span>>−1
</span></span>
было 77г зерна и 23 г воды
стало 77г зерна ---- 100-12 %
Хг зерна+воды ----- 100%
Х=77*100 /88=87,5 г стало весить зерно
100 -87,5=12,5 г потеряло зерно после просушки
100г ---- 100%
12,5г ----- Х%
Х=12.5%
Ответ 12.5%