Answer
$-1\not<-4$
Thus, $8$ is not in the solution set of $-y+7<-4$.
Work Step by Step
$-1$ is NOT less then $-4$ so the conclusion that $8$ is a solution of $-y+7<-4$ is wrong.
Since $-1\not<-4$, then $8$ is NOT in the solution set of $-y+7<-4$.