Question

Simplify (x − 4)(x2 + 3x + 2).

Answer 1

(x - 4) (x^2 + 3x + 2)
Multiply x from the first parentheses into the second set of parentheses
(x^3 + 3x^2 + 2x)
Multiply -4 from the first parentheses into the second set of parentheses
(-4x^2 - 12x - 8)
Add both equations together
(x^3 + 3x^2 + 2x) + (-4x^2 - 12x - 8) =
(x^3 - 1x^2 - 10x -8)

Answer 2

(x - 4)(x² + 3x +2)

The first you should have in your mind is the Distributive property

(x)(x²) + (x)(3x) + (x)(2) + (-4)(x²) + (-4)(3x) + (-4)(2)

= x³ + 3x² + 2x - 4x² - 12x -8

= x³ - x² - 10x - 8  

I hope that's help:)