So a good place to start is just to calculate these things ahead of time and then just substitute them back into the equation. So what's the mean of our x's? The mean of our x's is going to be 1 plus, I'll do the same colors, 1 plus 2 plus 4 divided by, I'll do this in a neutral color, the mean of our x's divided by 3. And what's this going to be? 1 plus 2 is 3 plus 4 is 7 divided by 3. It is equal to 7 over 3. Now, what is the mean of our y's?