Question

Let , $f\left(x\right)=x^2+5x+6$, then the number of real roots of $\left(f\right(x){)}^2+5f(x)+6-x=0$ is

• A. 1
• B. 2
• C. 3
• D. 0

Answer 1

The correct option is D

0

Use “f(x) = x has non real roots $\Rightarrow$ f(f(x)) = x also has non-real roots”