If `x^(2) + 4 = 29`, then `x^(2) - 4 = ?`

Options

A. 5
B. `sqrt(21)`
C. 21
D. 25

Answer

To solve the equation \( x^{2} + 4 = 29 \) and find the value of \( x^{2} - 4 \), we can follow these steps:

### Step 1: Solve for \( x^{2} \)
We start with the equation:
\[ x^{2} + 4 = 29 \]
To isolate \( x^{2} \), we subtract 4 from both sides:
\[ x^{2} = 29 - 4 \]
Calculating the right side gives:
\[ x^{2} = 25 \]

### Step 2: Substitute \( x^{2} \) into \( x^{2} - 4 \)
Now that we have \( x^{2} = 25 \), we can substitute this value into the expression \( x^{2} - 4 \):
\[ x^{2} - 4 = 25 - 4 \]
Calculating this gives:
\[ x^{2} - 4 = 21 \]

### Final Answer
Thus, the value of \( x^{2} - 4 \) is:
\[ \boxed{21} \]