Challenge: Graph two functions :)

Question

Write a program (in any language you like) that graphs two functions in a single Cartesian coordinate system.

Requirements:
(1) Your program should make a call to a function that contains the expression to be graphed.
(2) The user must change the expression inside the function before pressing <Run>.
(3) The user must input the following values in order: (lower bound for values of x), (upper bound for values of x) and (the value by which x-values will increment).
(4) The y-axis should be horizontal, and the x-axis should be vertical.

As a motivation, the program below (which I wrote in C++) graphs one function.
https://code.sololearn.com/c2MvIO3BBnBh/#cpp

TIP: Two-dimensional arrays might prove useful here. :) Good luck :)

Answer 1

I haven't implemented variable bounds yet but have some of the framework in place.
Everything else is good
input m and c on 1 line (accepts -ve decimal and fraction values)
https://code.sololearn.com/ci43Jy1TGOoo/?ref=app

Answer 2

https://code.sololearn.com/WEfflJx3Sus8/?ref=app