What is the letter ƒ in mathematics?

The letter f usually indicates that the equation is a function in the notation f(x). 

Example: f(x) = x + 1

It is a fancier/more proper replacement for the variable 'y'. The same is used for the letter g as in g(x) and h as in h(x). 

OR

It could just be a regular ole variable

Example: f + 1 = 7, solve for f

x = 25

step-by-step explanation:

a^2+b^2=c^2

7^2+24^2=c^2

49+576=625

sqrt625=25

x=25

idk

step-by-step explanation:

idk