please help with question 1a and 1b

(1) Acme Storage has equity with a market capitalization of $100 million. Acme's current debt-to-equity ratio is 0.4 and management intends to maintain this ratio. The required rate of return on the firm's debt is 7.4%. The corporate tax rate is 35% (a): If Acme's free cash flow is expected to be $7 million next year and is expected to grow at a rate of 3% per year, what is Acme's WACC? (hint: use the growing perpetuity formula) (b): What is the value of Acme's interest tax shield? (hint: compare the values of the firm under the WACC and pretax-WACC scenarios)