Hey CPhill, thanks for the help!
I still have one question based on your work : )
Here is the work:
[ f-1(a) - f-1(b) ] / [a - b] = ( [ (3/2)(a + 5] - (3/2)(b) + 5] / [ a - b] =
[ (3/2) (a - b) ] / [ a - b ] = 3/2
I don't understand the bolded out part, as in how you went from [ (3/2)(a + 5] - (3/2)(b) + 5] / [ a - b] to the next part..
Could you please further explain your steps, I am a little confused about that