we have that
4x–3y=12
Part 1) express y in terms of x
4x–3y=12---------> clear variable y
3y=4x-12
y=[4x-12]/3
y=(4/3)x-12/3
y=(4/3)x-4
the answer part 1) is
y=(4/3)x-4
Part 2) express x in terms of y
4x–3y=12-------> clear variable x
4x=3y+12
x=[3y+12]/4
x=(3/4)y+12/4
x=(3/4)y+3
the answer Part 2) is
x=(3/4)y+3