a) 2f(3) - 3f(2), when f(x) = x^2 - 5x + 5;
b) f^2(1) - f^2(0), when f(x) = √(x+1)(x+2)

First off, if given the function f(x) = x^2-5x+5 do you know how to calculate the value for f(3)? Just replace the 'x' in the formula with 3 and crank away. Try it, tell us what you get, and we'll help if you get stuck. But you must show us your attempt for further assistance.