To find the regular cost per month (m) that Spencer would have to pay without the discount, we can set up the equation based on the information given.
Spencer prepaid for 12 months of membership, which would normally cost \( 12m \) if there were no discount. Since he received a one-time discount of $35, the total amount he paid can be expressed as:
\[ 12m - 35 = 205 \]
Therefore, the equation that Spencer can use to find the regular cost per month \( m \) is:
\[ 12m - 35 = 205 \]