Evaluate the expression `3b-ac` when `a\ =\ 2`, `b\ =3`, and `c=-1.5`.
To evaluate the expression `3b-ac` when `a = 2`, `b = 3`, and `c = -1.5`, we substitute the given values into the expression.
`3b - ac` becomes `3(3) - 2(2)(-1.5)`.
Next, we simplify the expression inside the brackets:
`= 9 - 2(2)(-1.5)`
`= 9 - 2(-3)`
`= 9 + 6`
`= 15`
Therefore, the value of the expression `3b-ac` when `a = 2`, `b = 3`, and `c = -1.5` is 15.