Y-x=0
2x-5y=9
y-5=2x
y-3x=-1
anyone good at substitution that could do these two problems for me?

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! :-)