Question

2.
Let f(x)= x² and g(x)=x +3 then fog(x) =
A
X* +3
(x+3)
С
3
x + 3x
x? +3x
B
D​

Answer 1

f(x) = x² , g(x) = x + 3

fog(x), basically, is a composition of two functions f(x) and g(x). fog(x) may also be written as f[g(x)].

But, f(x) = x² ............... (a)

Replace x by g(x) in (a),

f[g(x)] = [g(x)]²

But, g(x) = x + 3,

=> f[g(x)] = (x + 3)²

Hence, fog(x) = (x+3)²