Question

If function $f:x\to 5x-7$, find the image of 8 and the pre image of 13.

Short answer

The image of 8 is 33 and the pre image of 13 is 4 for the function.

Step-by-step solution

Step 1. Given Information.

The given function is $f:x=5x-7$.

Step 2. Calculation.

Consider the given function $f:x=5x-7$. It can be also written as $f\left(x\right)=5x-7$.

To calculate the image, substitute 8 for $x$ in the function.

$\begin{array}{c}f\left(8\right)=5\times 8-7\\ =40-7\\ =33\end{array}$

To calculate the pre image, equate the function with the given value.

$\begin{array}{c}f\left(y\right)=13\\ 5y-7=13\\ y=4\end{array}$

Step 3. Conclusion.

Therefore, the image of 8 is 33 and the pre image of 13 is 4 for the function.