Question

Find the product:
(x² − 5x + 8) × (x² + 2)

Answer 1

By horizontal method:

$$\begin{gathered} (x^2-5x+8)\times (x^2+2) \\ =x^2(x^2-5x+8)+2(x^2-5x+8) \\ =x^4-5x^3+8x^2+2x^2-10x+16 \\ =x^4-5x^3+10x^2-10x+16 \end{gathered}$$