When x = 2, y = 50 and when x = 4, y = 100. which direct variation equation can be used to model this function?

Well, let's first write these as points.

( 2 , 50 )

( 4 , 100 )

We can see that when "x" is reduced by 2, "y" is reduced by 50. This means that if we reduce "x" by 1, "y" will be reduced by 25. Thus, we can say that if "x" is 1, "y" will be 25.

( 1 , 25 )

What we know that 25 * 1 = 25, and that 2 * 25 = 50. We can see that multiplying "x" by 25 will give us our "y". We can now write this as an equation.

y = 25x