Chapter 8, Problem 15CR

To determine

To simplify:The expression $(8z^3-3z^2-7)-(z^3-z^2+9)$

Answer to Problem 15CR

  $7z^3-2z^2-16$

Explanation of Solution

Given information:The expression $(8z^3-3z^2-7)-(z^3-z^2+9)$

Calculation:

  $\begin{array}{l}(8z^3-3z^2-7)-(z^3-z^2+9)\\ =8z^3-3z^2-7-z^3+z^2-9\\ =(8z^3-z^3)+(-3z^2+z^2)+(-7-9)[\text{grouping like terms]}\\ =7z^3-2z^2-16\end{array}$

Thus, $(8z^3-3z^2-7)-(z^3-z^2+9)=7z^3-2z^2-16$