1.) y-x=0 and 2x-5y=9
Lets take the first equation (since it is the easiest to use for the substitution process) and set y equal to x by adding x to both sides.
y=x
Then we will substitute this into the second equation like this...
2x-5(x)=9
2x-5x=9
Combine like terms...
-3x=9
Divide both sides by -3...
x=-3
^^^ That's the answer!
2.) y-5=2x and y-3x=-1
Again let's use the first equation and set I equal to y by adding 5 to both sides...
y=2x+5
Now let's substitute this into the second equation...
(2x+5)-3x=-1
2x+5-3x=-1
Now lets put the terms in order and then combine like terms...
-3x+2x+5=-1
-1x+5=-1
Now, let's subtract 5 to both sides...
-1x=4
Then divide both sides by -1...
x=4
^^^ That's the answer for #2!
Hope that helped! :-)
