Question 72830
Solve one of the equations for a single variable (I'm going to solve for y on the top). You then plug this y value into any y you see into the 2nd equation
{{{y=4-x}}}Solve for y
{{{-5+2(4-x)=-6}}}Now you can solve for x
{{{-5+8-2x=-6}}}
{{{-2x=-9}}}
{{{x=9/2}}}
Now plug this into x+y=4
{{{9/2+y=4}}}Solve for y
{{{y=4-9/2}}}
{{{y=(8-9)/2}}}
{{{y=-1/2}}}
So the solution is (9/2,-1/2) or (4.5,-0.5). In a nutshell you are substituting to eliminate one variable. This allows you to work with one variable, since you cannot simultaneously solve for 2 variables. You then take the answer of one and plug it in the other equation. Hope this helps.