Let's define the unknown number as \( x \).
According to the statement, "Half a number plus 9, is -7", we can translate it into the following equation:
\[ \frac{1}{2}x + 9 = -7 \]
Now, let's solve the equation step by step.
- Subtract 9 from both sides:
\[ \frac{1}{2}x = -7 - 9 \]
\[ \frac{1}{2}x = -16 \]
- Multiply both sides by 2 to solve for \( x \):
\[ x = -16 \times 2 \]
\[ x = -32 \]
Therefore, the solution is:
The number is -32.