Write a thorough discussion of the following capital expenditure valuation methods: payback; discounted payback; net present value (interrelate profitability index); internal rate of return; and modified internal rate of return. In this discussion consider the strengths and weaknesses (or positives and negatives) of each, compare to each other, what industries and/or types of businesses you would expect to see these tools used effectively, and which two you would employ in valuing a capital expenditure. Also provide illustrations of each valuation method.