How was this solved algebraically? the answer to the problem is at the bottom but but i dont know the steps it took to get to the answer

A stock has a of 0.5 and an expected return of 6%. Expected returns on the S&P 500 are 8%. What is the expected yield on T-bills?

Solution 3: E(Ri)= Rf+ i*[E(Rm)-Rf]

6 = Rf +0.5 [8-Rf]

Rf = 4%