(a) $V(x) = \left( x^{2} - 3x \right)\ J$
For a conservation field. Force, $F = - \frac{dV}{dx}$
$\therefore F = - \frac{d}{dx}\left( x^{2} - 3x \right) = - (2x - 3) = - 2x + 3$
At equilibrium position, $F = 0$
$- 2x + 3 = 0$
$x = \frac{3}{2}m = 1.5\ m$