7•y=100-9

To solve the equation \( 7y = 100 - 9 \), first simplify the right side:

\[ 100 - 9 = 91 \]

Now, the equation is:

\[ 7y = 91 \]

Next, divide both sides by 7 to isolate \( y \):

\[ y = \frac{91}{7} = 13 \]

So, the solution is \( y = 13 \).