1 1/2 of his total diet in gluten free and vegan
I do believe that that point is -2.2 because of the fact that the difference between -1.6 and -2.4 is 0.8, and there are 4 marks in between them. So each mark's value is decreased by -0.2.
There is no way to tell because there is no value for x and y. However just looking at the picture, I’m guessing m is around 45 degrees.