4 also 2 :))))))))))))))))
2x²+x-6=0
(2x-3)(x+2)=0
x=3/2 or -2
☺☺☺☺
1.5 cups of vegetable oil
You can find the remainder right away by simply plugging in

. The polynomial remainder theorem guarantees that the value of

is the remainder upon dividing

by

, but I digress...
Synthetic division yields
3 | 2 -11 18 -15
. | 6 -15 9
- - - - - - - - - - - - - - - - -
. | 2 -5 3 -6
which translates to

(and note that

, as expected)