Force acting on a particle varies with displacement as shown in figure. The work done from x=-4m  to x=+4m  is

Work done= Area of  $\text{Force}-displacement$ graph
W = Area of  $\Delta \text{BCD+Area of }\Delta \text{OAB+Area of }▭\text{OAEF+Area of }\Delta \text{EFG}$
W= $\left[\frac{1}{2}\times 2\times -6\right]+\left[\frac{1}{2}\times 2\times 6\right]+\left[2\times 6\right]+\left[\frac{1}{2}\times 2\times 6\right]$
Work done=12+6=18J