Q42. - Algebra 1

Question

Examples 4 and 5 If $f\left(x\right)=-2x-3$ and $g\left(x\right)=x^2+5x,$ find each value. (P. 50)

$f(r+2)$

Step-by-Step Solution

Answer

The function value at $x=r+2$ is $-2r-7$

Step 1. Interpreting of function.

$f\left(r+2\right)$ Indicates the value of function $f\left(x\right)$ at $x=r+2$

Step 2. Apply substitution method.

Substitute $x=r+2$ into the function $f\left(x\right)$

$f\left(r+2\right)=-2\left(r+2\right)-3$

Step 3. Further calculation :

$\begin{array}{l}f\left(r+2\right)=-2\left(r+2\right)-3\\ f\left(r+2\right)=-2r-4-3\\ f\left(r+2\right)=-2r-7\end{array}$

Thus, the function value at $x=r+2$ is $-2r-7$