To determine how many medium blue shirts the football club ordered, we'll follow these steps:
1. Identify given values:
- The total number of blue shirts ordered is 57.
- The number of small blue shirts ordered is 18.
- The number of large blue shirts ordered is 25.
- The number of medium blue shirts ordered is missing and needs to be found.
2. Set up the equation:
- The total number of blue shirts (57) is the sum of small, medium, and large blue shirts.
- Using the known quantities, our equation will be:
[tex]\[
\text{Total blue shirts} = \text{Small blue shirts} + \text{Medium blue shirts} + \text{Large blue shirts}
\][/tex]
- Substitute the given values into the equation:
[tex]\[
57 = 18 + \text{Medium blue shirts} + 25
\][/tex]
3. Simplify the equation:
- Combine the number of small and large blue shirts:
[tex]\[
57 = 18 + 25 + \text{Medium blue shirts}
\][/tex]
[tex]\[
57 = 43 + \text{Medium blue shirts}
\][/tex]
4. Solve for the number of medium blue shirts:
- Isolate the variable ([tex]\(\text{Medium blue shirts}\)[/tex]) by subtracting 43 from both sides of the equation:
[tex]\[
57 - 43 = \text{Medium blue shirts}
\][/tex]
[tex]\[
14 = \text{Medium blue shirts}
\][/tex]
Thus, the football club ordered 14 medium blue shirts.