$\int _ { a } ^ { b } f ( x ) d x = 2.5$

$\int _ { b } ^ { c } f ( x ) d x = - 5.0$

$\int _ { c } ^ { d } f ( x ) d x = 1.5$

1. $\int _ { c } ^ { a } f ( x ) d x$ 

   Hint (a):

   $-\left ( \int_{a}^{b}f(x)dx+\int_{b}^{c}f(x)dx \right )$

2. $\int _ { a } ^ { c } 2 f ( x ) d x$ 

   Hint (b):

   See the hint (a) and adjust the coefficient.

3. $\int _ { d } ^ { a } f ( x ) d x$ 

   Hint (c):

   See the hint in part (a).

4. $\int _ { c } ^ { c } f ( x ) d x$ 

   Hint (d):

   Look at the bounds of integration.