If $$x = \root 3 \of {{x^2} + 11} - 2{\text{,}}$$    then the value of x³ + 5x² + 12x is?

Solution (By Examveda Team)

$$\eqalign{ & x = \root 3 \of {{x^2} + 11} - 2 \cr & \Rightarrow x + 2 = \root 3 \of {{x^2} + 11} \cr & \Rightarrow {\text{Taking cube on both side}} \cr & \Rightarrow {\left( {x + 2} \right)^3} = {x^2} + 11 \cr & \Rightarrow {x^3} + 8 + 6x\left( {x + 2} \right) = {x^2} + 11 \cr & \Rightarrow {x^3} + 8 + 6{x^2} + 12x = {x^2} + 11 \cr & \Rightarrow {x^3} + 5{x^2} + 12x = 3 \cr} $$