Mary spent $45 at the mall. She bought lunch for $9. She bought 3 shirts at each. Which of the following equations could be used to find x ?

x = 12

Step-by-step explanation:

If Mary spent $45 altogether,

then she bought lunch for $9

so our equation now is

$45 = $9 + 3x

It is 3x because he bought 3 shirts and we used x because we didnt

now how much the price of those shirts were

$45 = $9 +3x

$45 - $9 = 3x

$45 - $9 = $36

$36 = 3x

$36 / 3 = 12

x = 12

Please mark this answer as the brainliest