Question

What is f(f(x))?

x4 + 2x2 + 1


x4 + 2x2 + 2


x4 + 2


x4 + 1

Answer 1

B. X⁴+2X²+2

Explanation:

If f(x) = x²+1, we are to find ff(x)

F(f(x)) = f(x²+1)

to get f(x²+1), we will have to substitute x as x²+1 in the function f(x) as shown;

F(x²+1) = (x²+1)²+1

Expand the expression

f(x²+1) = (x²+1)(x²+1)+1

f(x²+1) = (x⁴+x²+x²+1)+1

f(x²+1) = x⁴+2x²+1+1

f(x²+1) = x⁴+2x²+2

Hence f(f(x)) = x⁴+2x²+2