Amber Company has $$28$ million in assets, which were financed with $$8$ million of debt and $$20$ million in equity. Amber's beta is currently $1\mathrm{.}4,$ and its tax rate is $40\%.$

a$.$ Use the Hamada equation to find Amber's unlevered beta $($bu$).$

b$.$ What happens to Amber's beta if the company changes its capital structure to $$14$ million debt and $$14$ million equity?