Chapter 8, Problem 20CR

To determine

To simplify:The expression $-2n^2(5n-9+4n^2)$

Answer to Problem 20CR

  $-8n^4-10n^3+18n^2$

Explanation of Solution

Given information:The expression $-2n^2(5n-9+4n^2)$

Calculation:

  $\begin{array}{l}-2n^2(5n-9+4n^2)\\ =-2n^2(5n)-2n^2(-9)-2n^2(4n^2)[\text{distributing }-2n^2]\\ =-10n^3+18n^2-8n^4\\ =-8n^4-10n^3+18n^2[\text{writing in standard form]}\end{array}$

Thus, $-2n^2(5n-9+4n^2)=-8n^4-10n^3+18n^2$