If $\int_{1}^{5} f(x) d x=4$ And $\int_{5}^{8} f(x) d x=9$ , Evaluate $\int_{8}^{5} f(x) d x$

Short Answer

If $\int_{1}^{5} f(x) d x=4$ and $\int_{5}^{8} f(x) d x=9$ , evaluate $\int_{8}^{5} f(x) d x$ .