1. <span><span> {9x-7y=19</span></span>
<span><span><span> {-9x-4y=25.</span></span></span>
складываем
<span><span>9x<span>+(-9x)<span><span>-7y</span></span>+(-4y)<span><span><span><span><span>=19+</span></span></span></span></span>25.</span></span></span>
<span><span><span>-11y=44</span></span></span>
<span><span><span>y=-4</span></span></span>
<span><span><span>подставляем</span></span></span>
<span><span><span>9x-7*(-4)=19</span></span></span>
<span><span><span>9x=-9</span></span></span>
<span><span><span>x=-1</span></span></span>
<span><span><span>
</span></span></span>
<span><span><span>
</span></span></span>
<span><span><span>2.аналогично</span></span></span>
<span><span><span><span><span><span>y-x+7y-x=-3+<span><span><span><span><span><span>9</span></span></span></span></span></span></span></span></span></span></span></span>
<span><span><span><span><span><span><span><span><span><span><span><span>8y-2x=6</span></span></span></span></span></span></span></span></span></span></span></span>
<span><span><span><span><span><span><span><span><span><span><span><span>2x=8y-6</span></span></span></span></span></span></span></span></span></span></span></span>
<span><span><span><span><span><span><span><span><span><span><span><span>x=4y-3</span></span></span></span></span></span></span></span></span></span></span></span>
<span><span><span><span><span><span><span><span><span><span><span><span>y-4y+3=9</span></span></span></span></span></span></span></span></span></span></span></span>
<span><span><span><span><span><span><span><span><span><span><span><span>-3y=6</span></span></span></span></span></span></span></span></span></span></span></span>
<span><span><span><span><span><span><span><span><span><span><span><span>y=-2</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></span></span></span></span></span></span></span></span>
x=-8-3
<span><span><span><span><span><span><span><span><span><span><span><span>x=-11</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></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></span></span></span></span><span><span><span><span><span><span><span><span><span><span><span><span>3.<span><span><span>5x+y+<span>x+y=-10<span><span><span><span><span><span><span><span><span><span><span><span><span><span><span>+6</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></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><span><span><span><span><span><span> 6x+2y=-4</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></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><span><span><span><span><span><span> 2y=-4-6x</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></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><span><span><span><span><span><span> y=<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><span><span><span>-2-3x</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></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></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><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></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><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></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><span><span><span><span><span> 5x<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><span><span><span>-2-3x</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></span></span></span>=6 </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><span><span> 2x=8</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><span><span> x=4</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><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><span><span><span><span> y=-2-3*4</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><span><span> y=-14
</span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>
<span><span><span>
</span></span></span>
