Is there a way to plot a figure (Z), when the variable (Y) is a function of another variable (x)

What you demand with the notation you provide can't be done in neither version of Mathcad or Prime the way yu wrote it.

Not sure what you mean exactly but what you wrote looked like it should be done that way:

f(x):= 5x^3-2x+2 [or any other definition dependent n variable x]

Y(x):=f(x)

Z(x):=f(Y(x))

But it would be easier to define

f(x):= 5x^3-2x+2 [or any other definition dependent n variable x]

BTW, you won't need to define x as a range beforehand. You may define x as range before the plot but you could also use the quickplot feature.

Z(x):=f(f(x))

Hi,

"He has requested that we go back to an older version of MathCad because Prime can't do what he needs."

A common theme on this community.  You should at least try a little harder in Prime as eventually that is all that will be available.

What is the function f(x)?  Over what range is it plotted?

Cheers

Terry