The situation describes Michaela buying 3 necklaces at the same cost, represented by \( x \), and she purchased a bracelet for $10.
To express the total cost of the necklaces in terms of \( x \), you would calculate the cost of the necklaces as \( 3x \) (since she bought 3 necklaces). Then, you would add the $10 cost of the bracelet.
Therefore, the correct expression representing the total cost would be:
\[ 3x + 10 \]
So, the correct response is:
3x + $10