[填空题]
$\text { Let } f(x)=3 x^{2}-4 x \text {. The graph of } f \text { is shown in the following diagram. }$
1. Find $\int\left(3 x^{2}-4 x\right) \mathrm{d} x $.
2. Find the area of the region enclosed by the graph of f , the x -axis and the lines x=2 and x=4 .
