Asset W has an expected return of of 13.8 percent and a beta of 1.4. If the risk free rate is 5.4 percent complete the following table for portfolios of Asset W and a risk free asset.

Needing to find the Portfolio Expected Return and Portfolio Beta for 0%,25%, 50%, 75%, 100%, 125%, 150%?

The slope of a line.

This problem here has it laid out but I am not understanding how they get the equation, is there a better step by step you could help me with?