## Calculus Concepts: An Informal Approach to the Mathematics of Change 5th Edition

$x\approx4.953$
As $f(x)$ is given, this is the output value therefore we have to calculate the input value of $x$. $f(x)=2.5\times \ln x+3$ $7=2.5\times \ln x+3$ $4=2.5\times \ln x$ $\frac{4}{2.5}=1.6=\ln x$ $e^{1.6}=e^{\ln x}=x$ (Let both sides be exponents of the base e) $x\approx4.953$