Answer:
[tex]\huge\boxed{\overrightarrow{u}-\overrightarrow{v}=\left<-10;\ -3\right>}[/tex]
Step-by-step explanation:
[tex]\overrightarrow{u}=\left<-8;\ 4\right>;\ \overrightarrow{v}=\left<2;\ 7\right>\\\\\overrightarrow{u}-\overrightarrow{v}=\left<-8;\ 4\right>-\left<2;\ 7\right>=\left<-8-2;\ 4-7\right>=\left<-10;\ -3\right>[/tex]