A number, y, is equal to the difference of a larger number and 3. The same number is one-third of the sum of the larger number and 9. Which equations represent the situation?
a)x+y=3 and x-3y=-27
b)x+y=3 and x-3y=-9
c)x-y=3 and x-3y=-27
d)x-y=3 and x-3y=-9