Question

2abc-3ab A=2 b=-3 c=4

Answer 1

2(2)(-3)(4) - 3(2)(-3)

4(-3)(4) - 6(-3)

-12(4) - (-18)

-48 + 18

-30

Whenever there are two minus signs next to each other, your answer should become a positive.  If there is one minus sign and one addition sign, it will stay a negative sign.  If there are two addition signs, the addition sign will stay the same.
(-) (-) = +
(-) (+) = -
(+) (-) = -
(+) (+) = +