# Find equation from a graph if the curve goes through the origin

I know how to find the equation of a function like the following diagram that has y-intercept that is not the origin:

But how I would find the equation of the function if instead of the curve cutting the y-axis at (0 -8), it cut the y axis at (0, 0)?

For example, if you bring the -8 up to 0 to cross the x-axis, and the x=1 root "bounces" off the x-axis before going negative again at x=4, your equation would be something like -x*(x+1)*(x-1)^2*(x-4).