substitute x=3+12y into -2x-y=3
-2(3+12y) -y=3
distribute
-6-24y-y=3
combine like terms
-6 -25y =3
add 6 to each side
-25y =9
divide by -25
y =-9/25
now substitute into x=3+12y
x=3+12y
x=3+12(-9/25)
x=3-108/25
x= 75/25 -108/25
x=-33/25
Answer: x=-33/25, y=9/25
