Question

Find the product:

(x² − 5x + 8)(x² + 2)

Answer 1

By column method:
$$\begin{gathered} {\mathrm{x}}^2-5\mathrm{x}+8 \\ \underline{\times ({\mathrm{x}}^2+2)} \\ {\mathrm{x}}^4-5{\mathrm{x}}^3+8{\mathrm{x}}^2 \\ \underline{2{\mathrm{x}}^2-10\mathrm{x}+16} \\ \mathrm{Add}:{\mathrm{x}}^4-5{\mathrm{x}}^3+10{\mathrm{x}}^2-10\mathrm{x}+16 \\ \therefore ({\mathrm{x}}^2-5\mathrm{x}+8)({\mathrm{x}}^2+2)={\mathrm{x}}^4-5{\mathrm{x}}^3+10{\mathrm{x}}^2-10\mathrm{x}+16 \end{gathered}$$