To solve the equation \( 75 \div \_\_\_ = -75 \), we can follow these steps:
### Step-by-Step Solution:
1. **Set Up the Equation**:
We start with the equation given in the problem:
\[
75 \div x = -75
\]
Here, \( x \) is the unknown number we need to find.
2. **Rewrite the Division as a Fraction**:
We can express the division in terms of a fraction:
\[
\frac{75}{x} = -75
\]
3. **Cross-Multiply**:
To eliminate the fraction, we can cross-multiply:
\[
75 = -75x
\]
4. **Solve for \( x \)**:
Now, we need to isolate \( x \). To do this, we can divide both sides of the equation by -75:
\[
x = \frac{75}{-75}
\]
5. **Simplify the Fraction**:
Simplifying the fraction gives us:
\[
x = -1
\]
6. **Conclusion**:
Therefore, the value of \( x \) is:
\[
x = -1
\]
### Final Answer:
The missing number is \( -1 \).
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