Question

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

31 < –5x + 6
25 < –5x
–5 < x

The student should have added 6 to both sides instead of subtracting it.

The student divided 25/–5 incorrectly.

The student should have switched the direction of the inequality sign to get –5> x for a final answer.

Answer 1

The student should have switched the direction of the inequality sign to

get –5 > x for a final answer.

Explanation:

When multiplying or dividing an inequality by a negative "flip" the inequality sign

The student should have switched the direction of the inequality sign to

get –5 > x for a final answer.

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Note:

For a more conventional appearance the entire inequality can be flipped to

–5 < x