Answer:
(d) None of these
Explanation:
The area of a rectangle is the product of its length and width.
Application
Multiplying the length by the width, we get ...
A = (-x +4)(3x^2)
= (-x)(3x^2) +(4)(3x^2)
= -3x^3 +12x^2 . . . . . does not match any offered expression