`f(-3/2)`

`=2(-3/2)^3+3(-3/2)^2-8(-3/2)` `-12`

`=(-27/4)+(27/4)+12-12`

`= 0`

So yes, `-3/2` is a root of 2x3 + 3x2 − 8x − 12, since the function value is `0`.

Please support IntMath!