To find out how many more packs of erasers Miss Jones needs to buy, let's define \( x \) as the number of packs of erasers she needs to buy.
Given that she already has 12 erasers and needs a total of 50, we can express this situation as:
\[ 12 + 6x = 50 \]
Here, \( 6x \) represents the number of erasers in \( x \) packs (since you mentioned they are sold in packs of 6).
So the correct equation from your options is:
12 + 6x = 50