Given a+ib=2-3i, then a=2 and b=-3.

Answer

To solve the problem, we need to determine the values of \( a \) and \( b \) given the equation \( a + ib = 2 - 3i \).

### Step-by-Step Solution:

1. **Identify the given equation**:
\[ a + ib = 2 - 3i \]
Here, \( a \) is the real part and \( b \) is the coefficient of \( i \) (the imaginary part).

2. **Separate the real and imaginary parts**:
From the equation, we can see that:
- The real part on the left side is \( a \).
- The real part on the right side is \( 2 \).
- The imaginary part on the left side is \( b \).
- The imaginary part on the right side is \( -3 \).

3. **Set up equations based on the real and imaginary parts**:
From the comparison of the real parts:
\[ a = 2 \]
From the comparison of the imaginary parts:
\[ b = -3 \]

4. **State the values of \( a \) and \( b \)**:
Thus, we have found:
\[ a = 2 \quad \text{and} \quad b = -3 \]

5. **Conclusion**:
Therefore, the values of \( a \) and \( b \) are:
\[ a = 2 \quad \text{and} \quad b = -3 \]