For what value of kkk does the system have infinitely many solutions? {2x+5y=84x+10y=k\begin{cases} 2x + 5y = 8 \\ 4x + 10y = k \end{cases}{2x+5y=84x+10y=k
k=8k = 8k=8
k=16k = 16k=16
k=4k = 4k=4
No such value exists