please show all formulas used and working out

3. Lube Oil, a chain of automobile service stations, reports net income of $ 100 million after depreciation of $50 million. The firm has capital expenditures of $80 million, and the noncash working capital increased from $25 to $40 million. Estimate the firm's FCFE, assuming that the firm is all equity financed. 4. Lube Oil, in Question 3, paid a dividend of $20 million and bought back $25 million in stock. Estimate how much the cash balance of the firm changed during the year