we need to solve a system of equations
we will write them like
x-2y=3
-7x+6y=-45
we will multiply the first equation by 3
3x-6y=9
-7x+6y=-45
addig them both
-4x+0=36
divide by 4
-x=9
multiply by -1
x=-9
we have x=-9 and we will use it in our first equation x-2y=3
-9-2y=3
add 9 on both sides
-2y=12
divide by -2
y=-6
we have x=-9 and y=-6