(x•5)•3=345

To solve the equation \((x \cdot 5) \cdot 3 = 345\), we can follow these steps:

1. Simplify the left side: \[ (x \cdot 5) \cdot 3 = 15x \]

2. Set the equation: \[ 15x = 345 \]

3. Solve for \(x\) by dividing both sides by 15: \[ x = \frac{345}{15} \]

4. Calculate \(x\): \[ x = 23 \]

Therefore, the value of \(x\) is \(23\).