Question 8331
y=-x-2
y=-3x+4  <--multiply this set by -1 so that we cancel out the y.


y=-x-2
-y=3x+4


0=4x+2    <--subtract 2 from both sides
-2=(4x+2)-2
-2=4x      <--divide both sides by 4
{{{-2/4}}}={{{4x/4}}}
{{{-1/2}}}=x




In order to find out the value of y, multiply "y=-x-2" by -3 in order to cancel out the value of x  
y=-x-2
y=-3x+4  


-3y=3x+6
y=-3x+4 

-2y=2      <--divide both sides by -2
{{{-2y/-2}}}={{{2/-2}}}
y=-1


x={{{-1/2}}} and y=-1