Solve by Substitution :
// Solve equation [1] for the variable <span> y </span>
<span> </span>
[1] <span>y = </span><span>x </span>+ 12
// Plug this in for variable <span> y </span> in equation [2]
<span> [2] <span>2•</span>(<span>x </span>+12)<span> + 4x</span> = 27
</span><span> [2] <span>6x</span> = 3
</span>
// Solve equation [2] for the variable <span> x </span>
<span> [2] <span>6x = </span>3</span>
<span> [2] <span>x = </span>1/2</span>
<span>// By now we know this much :</span>
<span> <span> y = </span><span>x</span>+12</span>
<span> <span> x = </span>1/2</span>
<span>// Use the <span> x </span> value to solve for <span> y </span>
</span>
<span> <span> y = </span><span>(1/2)</span>+12 = 25/2 </span>Solution :<span> {<span>y</span>,<span>x</span>} = {<span>25/2</span>,<span>1/2</span>}</span>
<span>y=x+12;4x+2y=27 </span>Solution :<span><span> {y,x} = {25/2,1/2}</span>
</span>System of Linear Equations entered : [1] y=x+12
[2] 4x+2y=27
Equations Simplified or Rearranged :<span><span> [1] y - x = 12
</span><span> [2] 2y + 4x = 27</span></span>
