Solve the simultaneous equations: 2x+3y=10
x-y=5

Well first you would like to get like variables on each side for just one variable. for example: 

2x + 3y = 10 and x - y = 5

You  would change the x - y so that way the x variable would be isolated:

x = 5 + y

Now you must substitute the 5 + y into the other equation for x:

2(5 + y) + 3y = 10

10 + 2y + 3y = 10

Combine like terms 5y + 10 = 10

In this case it would be insolvable because it would change to 5y = 0

So let's try the other equation.

2x + 3y = 10

5y = 10

y = 2

Now substitute this into the other equation:

x - 2 = 5

x = 7

There is your two answers. 

x = 7 and y = 2