Question

2x - y - 4 = 0

3x + y - 9 = 0
What is the solution set of the given system?

Answer 1

if you add this equations, you get just simple equations.
1) you must find x from simple eq.
2) you must find y using known x, by using one of this eq.

Answer 2

5x - 13 = 0
5x = 13
x = 13 /5
2(13/5) - y - 4 = 0
5.2 - y - 4 = 0

1.2 -y = 0
-y = -1.2
y = 1.2
y = 6/5

Answer 3

Just add the first equation to the second equation to get to the first line in my answer.