Answer
$ f(70)=60$.
The government tax revenue is $\$70$ at the tax rate of $60\%$.
The point is $(70,60)$.
Work Step by Step
The given function is $f(x)=\frac{80x-8000}{x-110}$, $30\leq x\leq100$.
Replace $x$ with $70$.
$\Rightarrow f(70)=\frac{80(70)-8000}{70-110}$
Simplify.
$\Rightarrow f(70)=\frac{5600-8000}{-40}$
$\Rightarrow f(70)=\frac{-2400}{-40}$
$\Rightarrow f(70)=60$.
Hence, the government tax revenue is $\$70$ at the tax rate of $60\%$.
The point is $(70,60)$.
