6х-ху+30-5у=5х-ху+35-7у
х+2у= 5
10х-ху-40+4у=2х-10-ху+5у
8х-у=30
{х+2у=5
{8х-у=30. |*2
{х+2у=5
{16х-2у=60
__________
17х= 65
х=3 14/17
3 14/17+2у=5
2у=5-3 14/17
2у=1 3/17
у= 20/17*1/2
у=10/17
От: ( 3 14/17; 10/17)
<span>а) (3у</span>²<span>-3у+1)-(4у-2)= 3y</span>²-3y+1-4y+2=3y²-7y+3
<span>б) 4b</span>³(3b²+b)=4b^4(3b+1)<span>
</span>
Первое число - 100х + 10у + 7
Второе число - 700 + 10х + у
<span>(100х + 10у + 7)*3 - 17 = <span>700 + 10х + у</span></span>
<span><span><span>300х+30у+21-17= 700+10х+у</span></span></span>
<span><span><span><span>290х+29у=696 </span></span></span></span>
<span><span><span><span><span>10х+у=24 </span></span></span></span></span>
<span><span><span><span><span><span>т.е. х=2, подставим его в любое уравнение получим - у=4 ...От сюда... <span>числа 247 и 724</span></span></span></span></span></span></span>
<span><span><span><span><span><span><span>
</span></span></span></span></span></span></span>
<span><span><span><span><span><span><span>Проверка:</span></span></span></span></span></span></span>
<span><span><span><span><span><span><span><span>247*3=741</span></span></span></span></span></span></span></span>
<span><span><span><span><span><span><span><span><span>741-17=724</span></span></span></span></span></span></span></span></span>