there are a few types of variation in Algebra. Direct and Indirect variation are the main ones for basic Algebra. When you get a little higher in math, you'll learn about joint variation, combined variation, and partial variation.

Direct variation is y=kx. It's just like a linear equation (y=mx+b) but with no vertical shift (so b=0). Indirect variation is y=k/x, which is a hyperbolic function. what is 23xY=?