Express each of the following in the form b or bi, where b is a real number
`sqrt(-25)`

Answer

To express \(\sqrt{-25}\) in the form \(b\) or \(bi\), where \(b\) is a real number, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the expression**:
We start with the expression \(\sqrt{-25}\).

2. **Separate the negative sign**:
We can rewrite the square root of a negative number using the property of imaginary numbers:
\[ \sqrt{-25} = \sqrt{25} \cdot \sqrt{-1} \]

3. **Calculate the square root of 25**:
The square root of 25 is a real number:
\[ \sqrt{25} = 5 \]

4. **Identify the square root of -1**:
The square root of -1 is defined as the imaginary unit \(i\):
\[ \sqrt{-1} = i \]

5. **Combine the results**:
Now we can combine the results from steps 3 and 4:
\[ \sqrt{-25} = 5 \cdot i = 5i \]

6. **Express in the required form**:
We have expressed \(\sqrt{-25}\) in the form \(bi\) where \(b = 5\).

### Final Result:
\[ \sqrt{-25} = 5i \]