Let f: R → R be a differentiable function such that f^′(x)+f(x)=∫_0^2 f(t) d t. If f(0)=e^-2, then 2 f(0)-f(2) is equal to ____

Let $\displaystyle f: \mathbb{R} \rightarrow \mathbb{R}$ be a differentiable function such that $\displaystyle f^{\prime}(x)+f(x)=\int_0^2 f(t) d t$. If $\displaystyle f(0)=e^{-2}$, then $\displaystyle 2 f(0)-f(2)$ is equal to $\displaystyle \_\_\_\_$