$\alpha \beta  = \frac{c}{a} = \frac{{ - 3}}{1} =  - 3 < 0\beta  < 0$$\alpha  + \beta  = \frac{{ - b}}{a} = \frac{{ - 7}}{1} =  - 7 < 0 \Rightarrow \alpha  + \beta  + \beta  < 0 \Rightarrow \alpha  + 2\beta  < 0$$\left| {\alpha  + 2\beta } \right| + \left| \alpha  \right| - \left| \beta  \right| =  - (\alpha  + 2\beta ) + \alpha  - ( - \beta ) =  - \alpha  - 2\beta  + \alpha  + \beta  =  - \beta $