plotting how dependent variable changes

[Richard Lim]

Hi, I've been struggling with the following assignment that my professor gave me.
I ran a regression of wages on educ, educ^2, educ^3, and age.
The question was "using the regression results, plot how predicted wages change with education, holding age at 35.

However, I am quite confused which code should I use.
Here's what I used:

margin at (age=35)
marginsplot

However, it doesn't show a graph that I'd wished. What should I do?

[Maarten Buis]

margins, at(age=35) over(educ)
marginsplot

[Richard Lim]

margins, at(age=35) over(educ)
marginsplot

it works! thanks !