please help with excel step-by-step (detailed) much appreciated **IMPORTANT** PLEASE MAKE SURE TO USE EXCEL WITH FORMULAS

Coki Inc.'s capital structure consists of 80% debt and 20% common equity, its beta is 1.8, before tax cost of debt is currently at 12%, and its tax rate is 40%. However, the CFO thinks the company has too much debt, and she is considering moving to a capital structure with 40% debt and 60% equity with before tax cost of debt 6%. The risk-free rate is 5.0% and the market total return is 11%. By how much would the WACC change due to this shift in Coki's capital structure?

PLEASE HELP WITH EXCEL STEP-BY-STEP (IN FULL detail) much appreciated **IMPORTANT** I WANT TO LEARN