is this the one where i foil them with their according value? Or is something to do with finding the angle between?
You scale u by -4 (i.e. you multiply each component by -4) and then add the result to v (i.e. just add corresponding components).
-4<-7, 1> + <3, 17> → <28, -4> + <3, 17> → <31, 13>
.
+280 
