Using the tax rate schedule given here LOADING...$,$ perform the$$ following:

a$.$ Find the marginal tax rate for the following levels of sole proprietorship earnings before$$ taxes: $ $15000$; $ $60000$; $ $90000$; $ $150000$; $ $250000$; $ $450000$; and $ $1$ million.

b$.$ Plot the marginal tax rates$($measured on the $$y$-$axis$)$ against the pretax income levels$($measured on the $$x$-$axis$)$

$$0$ to $$9,875$ $$0+(10\%$ amount over $$0)$

$9,876$ to $40,125988+(12\%$ amount over $9,876)$

$40,126$ to $85,5254,618+(22\%$ amount over $40,126)$

$85,526$ to $163,30014,606+(24\%$ amount over $85,526)$

$163,301$ to $207,35033,272+(32\%$ amount over $163,301)$

$207,351$ to $518,40047,368+(35\%$ amount over $207,351)$

$518,401$ to Unlimited $156,235(37\%$ amount over $518,401)$