Question

Find the equation of the inverse.ormula1" title="y = {2}^{x + 5} - 6" alt="y = {2}^{x + 5} - 6" align="absmiddle" class="latex-formula">

Answer 1

Find the equation of the inverse.

$y = {2}^{x + 5} - 6$

we have

$y=\mleft\{2\mright\}^{\mleft\{x+5\mright\}}-6$

step 1

Exchange the variables

x for y and y for x

$x=\{2\}^{\{y+5\}}-6$

step 2

Isolate the variable y

$(x+6)=2^{(y+5)}$

apply log both sides

$\begin{gathered} \log (x+6)=(y+5)\cdot\log (2) \\ y+5=\frac{\log (x+6)}{\log (2)} \\ \\ y=\frac{\log(x+6)}{\log(2)}-5 \end{gathered}$

step 3

Let

$f^{(-1)}(x)=y$

therefore

the inverse function is

$f^{(-1)}(x)=\frac{\log(x+6)}{\log(2)}-5$