Evaluate the expression `3b-ac` when `a\ =\ 2`, `b\ =3`, and c=-1.5

12

-5

-15.5

24

To evaluate the expression `3b - ac` when `a = 2`, `b = 3`, and `c = -1.5`, we substitute the values in the expression:

`3(3) - 2(-1.5)`

Simplifying the expression gives us:

9 + 3

The final answer is:

12