If the function f:R → R be given by f(x) = x² + 2 and g :R → R be given by find fog and gof and hence find fog (2) and gof (– 3).

f(x) = x² + 2 and

let us find fog

⇒ fog = f(g(x))

Replace x by in f(x)

For fog(2) put x = 2

⇒ fog(2) = 6

Now let us find gof

⇒ gof = g(f(x))

⇒ gof = g(x² + 2)

Replace x by x² + 2 in g(x)

For gof(-3) put x = -3

Hence fog(2) = 6 and