Hello, tstaskal!

Do you understand functional notationat all?

Given a function means "replace each with ."

Do not know what to do for the following:

Find and simplify for each function:

We are asked to find; .

Try to "read" what is says:

. . (a) Find . . . replace with .

. . (b) Then find . . . replace with .

. . (c) Then subtract them: .

. .

. .

. .

Answer: .

You see? . . . It's just basic Algebra . . .