Q 15. Functions f , g : R → R are defined, respectively, by f (x) = x2 + 3x + 1,
g (x) = 2x – 3, find
(i) f o g (ii) g o f (iii) f o f (iv) g o g

Q26. Let * be the binary operation defined on Q. Find which of the following binary
operations are commutative
(i) a * b = a – b a, b ∈ Q (ii) a * b = a2 + b2 a, b ∈ Q
(iii) a * b = a + ab a, b ∈ Q (iv) a * b = (a – b)2 a, b ∈ Q