Dan started with 69 cards
Step-by-step explanation:
Let x be the initial number of cards
Then
According to "Dan bought 7 new baseball trading cards to add to his collection"
The next day his dog ate half of his collection.
There are now only 38 cards left.
Multiplying both sides by 2
Subtracting 7 from both sides
Hence,
Dan started with 69 cards
Keywords: Linear equation, word problems
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