7x -15 = 4x - 3(x-3).

To solve the equation \( 7x - 15 = 4x - 3(x-3) \), we will first simplify the right-hand side of the equation:

1. Distribute \(-3\) over the expression \( (x - 3) \): \[ -3(x - 3) = -3x + 9 \]

2. Substitute this back into the equation: \[ 7x - 15 = 4x - 3x + 9 \]

3. Simplify the right-hand side: \[ 4x - 3x + 9 = x + 9 \]

4. Now, the equation looks like: \[ 7x - 15 = x + 9 \]

5. Next, we will isolate \(x\). First, subtract \(x\) from both sides: \[ 7x - x - 15 = 9 \]

   Simplifying that gives: \[ 6x - 15 = 9 \]

6. Now, add \(15\) to both sides: \[ 6x = 9 + 15 \] \[ 6x = 24 \]

7. Finally, divide both sides by \(6\): \[ x = \frac{24}{6} = 4 \]

Thus, the solution to the equation \( 7x - 15 = 4x - 3(x - 3) \) is \( x = 4 \).