How can i get the variables on both sides in the equation-27-12y=3x?

Logan wants to know how many skateboards have defective parts. he inspects 20,000 skateboards and keeps track of the number of defects per board. use his probability distribution table to find the expected value for defects on a skateboard.

Write an equation for the function that includes the points (2,100)and (3,100)

Can you me find the missing length. i attached an image.