How to understand the MM theorem in the theory of capital structure in a popular way?

Without considering tax, the value of an enterprise is determined by its actual assets, not how these assets are raised, that is, the value of an enterprise has nothing to do with its capital structure. Proposition 2: The cost rate of equity capital of indebted enterprises is equal to the cost rate of equity capital of non-indebted enterprises plus a certain risk return rate, which is determined by multiplying the difference between the cost rate of equity capital of non-indebted enterprises and the cost rate of debt capital of indebted enterprises by the ratio of debt to equity. MM theory considering corporate tax: Proposition 1: In the case of considering corporate income tax, the value of a indebted enterprise is equal to the value of a debt-free enterprise with the same risk level plus the tax-free present value, and V (debt) =V (debt-free)+tax-free present value. The formula shows that the debt interest is tax-free because it is paid before the enterprise pays the income tax.