Find the student's error in solving the following inequality.

[tex]\[
\begin{array}{l}
31\ \textless \ -5x+6 \\
25\ \textless \ -5x \\
-5\ \textless \ x
\end{array}
\][/tex]

A. The student should have added 6 to both sides instead of subtracting it.
B. The student divided [tex]\(25\)[/tex] by [tex]\(-5\)[/tex] incorrectly.
C. The student should have switched the direction of the inequality sign to get [tex]\(-5\ \textgreater \ x\)[/tex] for a final answer.



Answer :

Let's evaluate the given inequality step by step and identify the student's mistakes.

The original inequality is:
[tex]\[ 31 < -5x + 6 \][/tex]

### Step 1: Subtract 6 from Both Sides

To isolate the term involving [tex]\(x\)[/tex], we first subtract 6 from both sides:
[tex]\[ 31 - 6 < -5x + 6 - 6 \][/tex]

This simplifies to:
[tex]\[ 25 < -5x \][/tex]

So far, the student performed this step correctly.

### Step 2: Solving for [tex]\(x\)[/tex]

Next, we need to solve for [tex]\(x\)[/tex] by dividing both sides of the inequality by [tex]\(-5\)[/tex]. When dividing by a negative number, the direction of the inequality sign must be flipped.

[tex]\[ \frac{25}{-5} > x \][/tex]

Dividing 25 by [tex]\(-5\)[/tex] yields:
[tex]\[ -5 > x \][/tex]

This means:
[tex]\[ x < -5 \][/tex]

### Mistakes Identified:

1. Direction of Inequality Sign: While the student correctly identified the need to divide by [tex]\(-5\)[/tex], they did not flip the inequality sign. The inequality should be [tex]\( x < -5 \)[/tex] instead of [tex]\( -5 < x \)[/tex].

2. Incorrect Final Inequality: The student's final answer was incorrect because they failed to switch the direction of the inequality sign, resulting in the wrong final inequality [tex]\( -5 < x \)[/tex].

### Conclusion:
The correct final inequality after solving [tex]\( 31 < -5x + 6 \)[/tex] should be:
[tex]\[ x < -5 \][/tex]