\((17)^{3.5}\times (17)^{?}=17^{8}\)
Answer: D
Let \((17)^{3.5}\times (17)^{x}=17^{8}\)
Then, \((17)^{3.5+x}=17^{8}\)
\(\therefore 3.5+x=8 \)
\(\Rightarrow x=(8-3.5) \)
\(\Rightarrow x=4.5\)