Jamal

Step 1: Set equation =0
. x2+4x−12=0
Step 2: Write quadratic equation as the product of two factors. (x+6)(x−2)=0
Step 3: Set each factor equal to 0. x+6=0
and x−2=0
Step 4: Solve each equation. x=−6
and x=2
George
Step 1: Begin with the equation. x2+4x−5=7
Step 2: Write quadratic equation as the product of two factors. (x+5)(x−1)=7
Step 3: Set each factor equal to 0. x+5=0
and x−1=0
Step 4: Solve each equation. x=−5
and x=1
When trying to solve the quadratic equation x2+4x−5=7
, Jamal and George each provided their work in the tables. Each said they used the Zero Product Property to solve the equation after step 2. Explain how you know the correct student’s solution is accurate and how you know the incorrect student’s solution is inaccurate.

(2 points)

Short Answer Rubric (2 points)
Points Awarded Criteria
2
The answer is very clear.

The answer is fully supported by details.

There may be a few errors in grammar, usage, or mechanics. Errors do not interfere with meaning.

1
The answer is somewhat clear.

Details are weak or not related.

There are some errors in grammar, usage, and mechanics. Errors interfere with meaning.

0 The question is not answered.
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1 answer

To determine which student's solution is accurate, we need to analyze the steps taken by both Jamal and George in solving the quadratic equation \(x^2 + 4x - 5 = 7\).

First, we should rewrite George's equation \(x^2 + 4x - 5 = 7\) in standard form:

  1. Subtract 7 from both sides: \[ x^2 + 4x - 5 - 7 = 0 \implies x^2 + 4x - 12 = 0 \]

Now we can evaluate both students based on the original equation:

1. Jamal's Solution:

  • Jamal correctly rewrote the equation as \(x^2 + 4x - 12 = 0\).
  • He factored it correctly into \((x + 6)(x - 2) = 0\).
  • Jamal then set each factor equal to zero:
    • \(x + 6 = 0 \implies x = -6\)
    • \(x - 2 = 0 \implies x = 2\)

Therefore, Jamal has correctly applied the Zero Product Property after moving all terms to one side.

2. George's Solution:

  • George started with the equation \(x^2 + 4x - 5 = 7\) but did not bring it to the correct standard form \(x^2 + 4x - 12 = 0\). He incorrectly wrote it as \((x + 5)(x - 1) = 7\), which is not the correct factorization of the standard form.
  • Because he did not solve the equation correctly, applying the Zero Product Property to his incorrect factors leads to erroneous solutions: \(x = -5\) and \(x = 1\).

Conclusion: Jamal's solution is accurate because he properly transformed the equation into standard form \(x^2 + 4x - 12 = 0\) and factored it correctly. In contrast, George's solution is inaccurate because he did not correctly rearrange the equation before factoring, resulting in an incorrect application of the Zero Product Property. This analysis demonstrates that Jamal’s approach and final solutions of \(x = -6\) and \(x = 2\) are valid, while George’s conclusions are based on an incorrect factorization and thus are invalid.