Chapter 4.6, Problem 4WE

To determine

The multiplication of two expressions $r^2+2r-5$ and $3r-2$ by using the vertical form.

Answer to Problem 4WE

  $3r^3+4r^2-19r+10$

Explanation of Solution

Given information : Two expressions:

  $\underset{\_}{\begin{array}{l}{r}^2+2r-5\\ 3r-2\end{array}}$

By using vertical form multiplication,

Firstly, we will multiply the ( $r^2+2r-5$ ) with -2 and ( $r^2+2r-5$ ) with $3r$ then combine the like terms.

  $\begin{array}{l}{r}^2+2r-5\\ 3r-2\\ \overline{-2r^2-4r+10}\\ \underset{\_}{3r^3+6r^2-15r}\\ 3r^3+4r^2-19r+10\end{array}$