Tyrianne solved a quadratic equation. Her work is shown below.

In which step did Tyrianne make an error?

[tex]\[
\begin{array}{l}
\frac{1}{2}(x+4)^2-3=29 \\
\frac{1}{2}(x+4)^2=32 \\
\text{Step 1} \\
(x+4)^2=64 \\
x+4= \pm 8 \\
\text{Step 2} \\
x=4 \text{ or } x=-12 \\
\end{array}
\][/tex]

A. Step 3

B. Step 4



Answer :

Let's carefully analyze each step of Tyrianne's work to identify the error.

1. Original Equation:
[tex]\[ \frac{1}{2}(x+4)^2 - 3 = 29 \][/tex]
2. Isolating the squared term:
[tex]\[ \frac{1}{2}(x+4)^2 = 29 + 3 \][/tex]
[tex]\[ \frac{1}{2}(x+4)^2 = 32 \][/tex]

So far, these steps are correct.

3. Removing the fraction by multiplying both sides by 2:
[tex]\[ (x+4)^2 = 32 \times 2 \][/tex]
[tex]\[ (x+4)^2 = 64 \][/tex]

This step is correct. However, in Tyrianne's work, she did:

[tex]\[ (x+4)^2 = 16 \][/tex]

This is incorrect. The correct value should be 64, not 16.

4. Taking the square root of both sides:
[tex]\[ x+4 = \pm \sqrt{64} \][/tex]
[tex]\[ x+4 = \pm 8 \][/tex]

This should follow correctly if Step 3 was done properly.

5. Solving for x:
[tex]\[ x = -4 + 8 \quad \text{or} \quad x = -4 - 8 \][/tex]
[tex]\[ x = 4 \quad \text{or} \quad x = -12 \][/tex]

These solutions would be correct if all steps were done correctly.

Therefore, the error occurred in Step 2 when she incorrectly solved:
[tex]\[ (x+4)^2 = 16 \][/tex]
Instead of correctly solving as:
[tex]\[ (x+4)^2 = 64 \][/tex]

Thus, Tyrianne made an error in Step 2.