-3x+y = -28
-x-6y = -3
~~~~~~~~~~~~~
Eliminate x:
-3x+y=-28
-x-6y=-3
~~~~~~~~~~~~~
-3x+y=-28
-3(-1)x-3(-6)y=(-3)(-3)
~~~~~~~~~~~~~
3x-1y=28
3x+18y=9
19y=-19
Therefore:
19y=-19
÷19 ÷19
y=
y=1
~~~~~~~~~~~~~
3x-1y=28
y=-1
~~~~~~~~~~~~~
3x-1(-1)=28
3x+1=28
-1 -1
3x=28-1
3x=27
÷3 ÷3
x=
↑ They cancel each other out
x=9
~~~~~~~~~~~~~
x=9
y=-1
Answer is: (9,-1)