$2x^2-x-28<0$  

$\Delta ={\left(-1\right)}^2-4\cdot 2\cdot \left(-28\right)=1+224=225$ $\Delta ={\left(-1\right)}^2-4\cdot 2\cdot \left(-28\right)=1+224=225$  

$\sqrt{\Delta }=15$  

$x_1=\frac{-\left(-1\right)-15}{2\cdot 2}=\frac{1-15}{4}=\frac{-14}{4}=-3\frac{1}{2}$  

$x_2=\frac{-\left(-1\right)+15}{2\cdot 2}=\frac{1+15}{4}=\frac{16}{4}=4$  

$x\in \left\{-3,-2,-1,0,1,2,3\right\}$  

 

Odp. B