Please show all work. Little if any credit will be given to answers without supporting to work.

A firm earned a profit of $$500$ million last period. The marginal tax rate is $40\%$ tax. Depreciation and interest expense were $$10$ million and $$25$ million, respectively. The firm invested $$30$ million in fixed capital necessary to sustain the business and invested $$70$ million in net working capital.

Compute the firm's FCFF$.$