Please show calculations as well as complete sentences. Using the financial statements provided below to answer the following questions:

a$.$ What was the book value of Nova's shareholders' equity from $2015$ to $2017?$ What were Nova's debt$-$to$-$assets and times$-$interest$-$earned ratios in these years? $($Use pretax income plus interest expense as EBIT.$)$ What do these figures suggest about Nova's use of financial leverage? Consulting Table $6-5$ in the text, what bond rating would Nova have in $2016$ if the rating were based solely on the firm's coverage ratio?

b$.$ What percentage decline in EBIT could Nova have suffered in each year before Nova would have been unable to make its interest payments out of operating income?

c$.$ Assuming a $35$ percent corporate tax rate, and $2016$ earnings before interest and taxes of $$895$ million, by how much did Nova's $$60$ million interest expense reduce taxes?

d$.$ Answer question $($a$)$ and $($b$)$ again for $2016$ assuming the company had borrowed an additional $$3$ billion in debt at $8$ percent interest at the start of the year and distributed the proceeds to shareholders as a special dividend. You may ignore the effect of added interest expense on Nova's balance sheet. Might shareholders benefit from such an increase in financial leverage? Enlain.

e$.$ Based on your analysis, is Nova heavily or modestly indebted? Should the company acquire more debt, or shed existing debt? Why?