Question

x - y = 19
2x + y = 2

Answer 1

set one up as y=
and then plug that back into the other equation(the substitution method)

Answer 2

x - y = 19 --> x = 19 - y
now sub 19 - y in for x in the other equation. This will allow you to solve for y.
Once you have solved y, sub that in to either of the equations and solve for x.
You can then check your answer by subbing in known values and if it comes out equal, you have solved it correctly, If not, then there was a mistake made.

Answer 3

Unless you were told to use substitution method, the elimination method is ideal for this system.

An inspection shows, that all that has to be done is to add the two equations. When add you now have this equation: 3x=21
You see x can be solved quickly, then as mentioned by kelliegirl33 substitute the value obtained for x and solve y.

Answer 4

radar is correct....elimination would be easier .