<span><span>{2x-y = -5 => -y=-5-2x /*(-1) y=2x+5
{-x+-y =10</span></span>
<span><span><em> Substitute y in the second equation:</em></span></span>
<span><span>-x-y=10</span></span>
<span><span>-x-(2x+5)=10</span></span>
<span><span>-x-2x-5=10</span></span>
<span><span>-3x-5=10 /+5</span></span>
<span><span>-3x=15 /:(-3)</span></span>
<span><span>x=-5</span></span>
<span><span>y=2x+5=2*(-5)+5=-10+5=-5</span></span>
<span><span>y=-5</span></span>
<span><span><u>Solution:</u> (-5; -5)</span>
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