College

Clara solved the equation [tex]\frac{7}{3} x = -\frac{2}{3}[/tex] as shown. What is Clara's error?

A. Clara should have divided by [tex]\frac{3}{7}[/tex].
B. Clara should have added [tex]\frac{7}{3}[/tex].
C. Clara should have multiplied by [tex]\frac{7}{3}[/tex].
D. The solution is [tex]-\frac{2}{7}[/tex], not -14.

[tex]\begin{aligned}
\frac{7}{3} x\left(\frac{3}{7}\right) & =-\frac{2}{3}\left(\frac{3}{7}\right) \\
x & =-14
\end{aligned}[/tex]

Answer :

To determine Clara's error in solving the equation [tex]\(\frac{7}{3} x = -\frac{2}{3}\)[/tex], let's go through the steps to solve it correctly:

1. Original Equation: [tex]\(\frac{7}{3} x = -\frac{2}{3}\)[/tex].

2. Isolate [tex]\(x\)[/tex]: To solve for [tex]\(x\)[/tex], we need to get rid of the fraction [tex]\(\frac{7}{3}\)[/tex] that's multiplying [tex]\(x\)[/tex].

3. Multiply by the Reciprocal: Multiply both sides of the equation by the reciprocal of [tex]\(\frac{7}{3}\)[/tex], which is [tex]\(\frac{3}{7}\)[/tex].

[tex]\[
\left(\frac{7}{3} x\right) \times \left(\frac{3}{7}\right) = \left(-\frac{2}{3}\right) \times \left(\frac{3}{7}\right)
\][/tex]

4. Simplifying:
- On the left side: [tex]\(\frac{7}{3} \times \frac{3}{7} = 1\)[/tex], so we get [tex]\(x\)[/tex].
- On the right side: Calculate [tex]\(-\frac{2}{3} \times \frac{3}{7} = -\frac{6}{21}\)[/tex].

5. Simplified Result: Simplify [tex]\(-\frac{6}{21}\)[/tex]. Both 6 and 21 are divisible by 3.

[tex]\[
-\frac{6}{21} = -\frac{2}{7}
\][/tex]

6. Conclusion: So the correct solution is [tex]\(x = -\frac{2}{7}\)[/tex].

Clara's Error: Clara's error arose from an incorrect simplification after multiplying by the reciprocal. She concluded that the solution was [tex]\(x = -14\)[/tex], which is incorrect. The correct solution is [tex]\(x = -\frac{2}{7}\)[/tex].