The sum of the maximum and minimum values of the function f(x)=|5 x-7|+[x^2+2 x] in the interval [5/4, 2], where [t] is the greatest integer ≤ t, is…

The sum of the maximum and minimum values of the function $\displaystyle f(x)=|5 x-7|+\left[x^2+2 x\right]$ in the interval $\displaystyle \left[\frac{5}{4}, 2\right]$, where $\displaystyle [t]$ is the greatest integer $\displaystyle \leq t$, is \_\_\_\_.