How to add a expression like this

i have been following a script but could figure out to add such can someone helpme
Its an important part to add up

expression - x(x+1)R

Assigned to Grasshopper category.

doubleclick on the canvas.
in the searchfield write
you should get a component like this - the expression component:

Screenshot 2022-12-08 at 00.36.52

zoom in to delete and edit parameters / input / output
(change “Variable x” to x, delete Variable y)

doubleclick on the formula and replace it with x+1

thankyou it worked