Hello!
First you have to find the cost of one slice of pizza
6/4 = 1.5
Then you make a equation that represent how much each pizza slice cost
1.5x = y
Then you graph this
You can use the points (2, 3), (0,0) and (-2, -3)
Draw a line through those 3 points that keeps going and add arrows to the ends of the lines
Hope this helps!