Answer
a. $T(5000)=0$.
$T(12000)=960$,
$T(25000)=5350$.
b.For Income of $5000$, Income tax is $0$.
For Income of $12000$, Income tax is $960$.
For Income of $25000$, Income tax is $5350$.
Work Step by Step
$T(x)=$$\begin{cases}
0&if&0\leq x\leq10,000\\
0.08x&if&10,000\lt x\leq20000\\
1600+0.15x&if&20000\lt x
\end{cases}$
a. Since $5000\lt10000,$ $T(5000)=0$.
Since $10000\lt12000\leq20000,$ $T(12000)=0.08(12000)=960$,
Since $20000\lt25000,$ $T(25000)=1600+0.15(25000)=5350$.
b. For Income of $5000$, Income tax is $0$. For Income of $12000$, Income tax is $960$ For Income of $25000$, Income tax is $5350$
