Suppose $\displaystyle \int_{-9}^{-4.5} f(x) dx =10, \ \int_{-9}^{-7.5} f(x) dx=8, \ \int_{-6}^{-4.5} f(x)dx =10$.

$\displaystyle \int_{-7.5}^{-6} f(x)dx =$

$\displaystyle \int_{-6}^{-7.5} (10 f(x)- 8)dx =$