Question

Simplify.

(x – 3)(x2 – 4x – 7)

A.
x3 – 3x2 + 12x + 21

B.
x3 – 7x2 + 19x + 21

C.
x3 – 7x2 + 5x + 21

D.
x3 + x2 – 5x – 21

Answer 1

(x-3)(x²-4x-7)=x(x²-4x-7)-3(x²-4x-7)=x³-4x²-7x-3x²+12x+21=
=x³+(-4x²-3x²)+(-7x+12x)+21=x³-7x²+5x+24

Answer: C. x³-7x²+5x+24

Answer 2

(x-3)(x²-4x-7)
=x(x²-4x-7)-3(x²-4x-7)
=x³-4x²-7x-3x²+12x+21
=x³+(-4x²-3x²)+(-7x+12x)+21
=x³-7x²+5x+21
C is right answer
hope this helps