Math homework help? please !?

Question

So, i have this big test tomorrow & i seriously don’t know how to do this.
It says; solve the system using the method of your choice and tell how many solutions the system has.
1) x + 2y = 5
2x - 2y = 4.
2) x+y=1
X+y=3
How many different solutions does it each have? Please help me.

Answer 1

 

x + 2y = 5 -----------> 1
2x - 2y = 4 --------------> 2
add equation 1 and 2
x + 2y = 5
2x - 2y = 4
------------------
3x = 9
divide each side by 3
x = 3
substitute x = 3 in x +2y = 5
3 +2y = 5
2y = 2
y = 1
(x, y) = (3, 1)
2.
Both lines are parallel to each other and they never intersect. No solution.