Answer:
x=8, y=4
Explanation:
I solved it using the substitution method, but any works really.
x+y=12
x-2y=0
x=12-y
Plug in given value of x:
12-y-2y=0
12-3y=0
-3y=-12
y=4
Plug in given value of y into first equation:
x+y=12
x+4=12
x=12-4
x=8
We can also do this using the Gauss method:
x+y=12 (Multiply this equation by -1)
x-2y=0
-x-y=-12 (Add both equations together)
x-2y=0
x-x-2y-y=-12+0 (Cancel out x and -x)
-3y=-12
y=4
Plug in given value of y:
x+y=12
x+4=12
x=8
Hope this helps!