Solve the equation for y and simplify.
x - 6y = 48

Start by simply rewriting the equation
x-6y=48
Then transfer any other variables or numbers through addition or subtraction so that the y is isolated on one side of the equals sign
(in this case, subtract the x so that it moves to the other side of the equal sign)
-6y =48 -x
Finally, do any multiplication or division to cancel out anything still attached to the y.
y = -8 +
(in this case, divide by -6)
Now the y has been fully isolated on one side of the equal sign and you can see that x - 6y = 48, solved for y, is y = -8 +.
I do not see any way to simplify this further, though it is possible I am missing something.