Q39. - 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)

$f\left(4y\right)$

Step-by-Step Solution

Answer

The function value at $x=4y$ is $-8y-3$.

Step 1. Interpreting of function.

$f\left(4y\right)$ Indicates the value of function $f\left(x\right)$ at $x=4y$

Step 2. Apply substitution method.

Substitute $x=4y$ into the function $f\left(x\right)$

width="131" style="max-width: none; vertical-align: -5px;" $f\left(4y\right)=-2\left(4y\right)-3$

Step 3. Further calculation :

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

Thus, the function value at $x=4y$ is $-8y-3$