Let x be the number we are looking for; therefore, 7 times a number is '7x'.
Then, 3.5 added to 7 times a number is
[tex]3.5+7x[/tex]Thus, the whole equation is
[tex]\begin{gathered} 3.5+7x=65.1 \\ \Rightarrow7x=65.1-3.5=61.6 \\ \Rightarrow x=\frac{61.6}{7}=8.8 \end{gathered}[/tex]Hence, the number is 8.8