I just finished working out this problem and I'm not very sure if I did it correctly
For a) The formula I wrote out is f(x) = 0.0685(x) + 973 which would give me a taxable income of 4261. Can you check if the formula is correct?
For b) Since they didn't give me a real income to go on, I just wrote out the formula for whatever the lawyer's income could be which is T(x) = 0.8(x), x = income. I don't know if that is correct by multiplying it by 0.8 or should the formula be T(x) = x - 20000, x = income. Please check if this is correct.
For c) L(x) = (T(x) - 20000)(0.0685) + 973
Please check if this formula is correct
For d) I just used the above formula and placed in 85000 for x.
Thanks in advance