A particle moving along x-axis has potential energy $\mathrm{U}$ = 2-20x+5x²J along the x-axis.  The particle is released at x=-3.  The maximum value of x will be    

$$\begin{gathered} \mathrm{F}=-\frac{\mathrm{dU}}{\mathrm{dx}} \\ \mathrm{and} \mathrm{F}=0 \mathrm{at} \mathrm{x}=2 \mathrm{m} \mathrm{and} \mathrm{f} \mathrm{is} \mathrm{proportional} \mathrm{to} -\mathrm{x} \mathrm{so} \mathrm{shm} \end{gathered}$$

so the amplitude is from -3 to +2  that is 5 m  and x=2 is the equilibrium position.

Maximum value of x on the other side 2+5= 7 m