We have the expression:

lets divide all by 2, this way our equation will be in a better form to understand it:

lets find where this line cuts the X axis and Y axis, wich means, find the point with X=0 and other point with Y=0, as follows:

so, our graph has the point (3,0), now lets find where it cuts the X axis:

So, our graph has the point (0,-3/2), with those informations, lets draw our graph: