Suppose that the functions r and s are defined for all real numbers x as follows.

Question

r（2） =3x-2
s（x）=x+2
Write the expressions for (r+s) (x) and (r-s) (x) and evaluate (r-s) (3).
(r+ s) (x) =

Answer 1

r(x) + s(x) = (3x-2) + (x+2) = 4x

(r- s) (x) = r(x) - s(x) = (3x-2) - (x+2) = 2x - 4

To evaluate (r-s)(3), plug in x=3:

(r-s)(3) = 2(3) - 4 = 6 - 4 = 2