Chapter 1.2, Problem 1E

To determine

To find the values of $f\left(4\right),f\left(8\right)\text{and}f\left(13\right)$

Answer to Problem 1E

  $\begin{array}{l}f\left(4\right)=-12\\ f\left(8\right)=-22\\ f\left(13\right)=-36\end{array}$

Explanation of Solution

Given:

  $f\left(x\right)=\sqrt{x-4}-3x$

Calculation:

Substituting x = 4 in $f\left(x\right)$ , we get

  $f\left(4\right)=\sqrt{4-4}-3\left(4\right)=-12$

Substituting x = 8 in $f\left(x\right)$ , we get

  $\begin{array}{l}f\left(8\right)=\sqrt{8-4}-3\left(8\right)\\ =\sqrt{4}-24\\ =2-24\\ =-22\end{array}$

Substituting x = 13 in $f\left(x\right)$ , we get

  $\begin{array}{l}f\left(13\right)=\sqrt{13-4}-3\left(13\right)\\ =\sqrt{9}-39\\ =3-39\\ =-36\end{array}$