College

Clara solved the equation [tex]\frac{7}{3} x = -\frac{2}{3}[/tex] as shown:

[tex]\begin{aligned}

\frac{7}{3} \times\left(\frac{3}{7}\right) & = -\frac{2}{3}\left(\frac{3}{7}\right) \\

x & = -14

\end{aligned}[/tex]

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.

Answer :

To solve the equation [tex]\(\frac{7}{3} x = -\frac{2}{3}\)[/tex] correctly, let's go through the process step-by-step:

1. Identify the operation needed to solve for [tex]\(x\)[/tex]:
The equation given is [tex]\(\frac{7}{3} x = -\frac{2}{3}\)[/tex]. To isolate [tex]\(x\)[/tex], we need to get rid of the fraction [tex]\(\frac{7}{3}\)[/tex] that is multiplying [tex]\(x\)[/tex].

2. Multiply by the reciprocal:
The simplest way to eliminate the fraction is to multiply both sides of the equation by the reciprocal of [tex]\(\frac{7}{3}\)[/tex], which is [tex]\(\frac{3}{7}\)[/tex].

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

3. Simplify the left side of the equation:
[tex]\(\frac{7}{3} \times \frac{3}{7} = 1\)[/tex], so the left side simplifies to:

[tex]\[
1 \times x = x
\][/tex]

4. Simplify the right side of the equation:
Multiply [tex]\(-\frac{2}{3}\)[/tex] by [tex]\(\frac{3}{7}\)[/tex]:

[tex]\[
-\frac{2}{3} \times \frac{3}{7} = -\frac{2 \times 3}{3 \times 7} = -\frac{6}{21}
\][/tex]

Simplifying [tex]\(-\frac{6}{21}\)[/tex], we divide both the numerator and the denominator by their greatest common divisor, which is 3:

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

5. Write the final solution:
Therefore, the correct solution is:

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

Clara's mistake was in the final calculation of the solution. She incorrectly stated that [tex]\(x = -14\)[/tex] instead of the correct solution, which is [tex]\(x = -\frac{2}{7}\)[/tex].