How to see if a graph is linear. I'm Bon Crowder with Math4.com and we're talking about how can you tell if a graph is linear. There are two ways to tell if a graph is linear. First of all the shape of the graph is a straight line. Every linear graph is nothing more than a straight line so if there is any curvies in it, it's not linear. The other way to tell is look at its equation. If the equation can be shaped into Y = MX + B where M and B are numbers, then it's going to be a linear equation. I'm Bon Crowder with Math4.com and that's how you can tell if a graph is a linear equation.