Answer
f is increasing in $(-\infty, \frac{7}{4})$ and f is decreasing in $(\frac{7}{4},+\infty)$
Work Step by Step
$f(x)=-2x^{2}+7x+14$
$f'(x)=-4x+7$
$f'(x)=0 \rightarrow -4x+7=0 \rightarrow x=\frac{7}{4}$
a<0 so we have: f is increasing in $(-\infty, \frac{7}{4})$ and f is decreasing in $(\frac{7}{4},+\infty)$
