I have $\displaystyle d^2x/dt^2+2dx/dt-2=e^(-t)$ and I have found CF = $\displaystyle A+Be^(-2t)$

I need to find the PI, usually I differentiate everything until you have a constant on the right or with an exp I would set $\displaystyle x= e^(-t)v(t)$ but neither seems to work, could someone help me with the method, thanks