We figured that out in part b of this problem. And then we could also express this, we saw that we could also write that as two minus two x plus y if you just substitute, if you substitute this in for that. So it's two minus two x plus y. So let me write it that way. So this is also equal to two minus two x plus y. So that's everything we know before we even thought that maybe there's a solution of y equals mx plus b. So now let's start with y equals mx plus b.