shelby had $18.50. She spent $7.25 at the car wash. Write an expression that shows how much she spent.

You have just said that she spent $7.25. There is no need for an equation.

However, if you want to know how much she has left:

$18.50 - $7.25 = ?

I hope this helps. Thanks for asking.

(18.50 -7.50)

To write an expression that shows how much Shelby spent, we need to subtract the amount she spent from the amount she had.

Shelby spent $7.25 at the car wash.

So, the expression that shows how much she spent can be written as:

$18.50 - $7.25

To simplify this expression, subtract the values:

$18.50 - $7.25 = $11.25

Therefore, Shelby spent $11.25.