<span>7x-2y=1</span>
<u><span><span>5x+3y=14</span></span></u>
12х+у=15 сумма двух уравнений
<span><span>у=15-12х</span></span>
<span><span>7х-2*(15-12х)=1</span></span>
<span><span>7х-30+24х=1</span></span>
31х=30+1
31х=31
х=1
7*1-2у=1
-2у=1-7
2у=6
у=3
7*1-2*3=7-6=1
5*1+3*3=5+9=14
<span><span>
</span></span>
Р=18х
меньш.сторона = 4х => 18х/ 4х = 9/2 ( или 4.5)
9900
9090
9009
..........
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