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Marla solved the inequality below incorrectly. What mistake did she make?

a
She added 3.5 to both sides when she should have subtracted.
b
She should have divided both sides by negative 5 as her first step.
c
She should not have flipped the inequality symbol in her answer
d
She should have divided 10 by negative 5 and gotten a -2

1 Answer

2 votes

Answer:

D) She should have divided 10 by negative 5 and gotten a -2

Explanation:

The question is incomplete. Here is the complete question.

"Marla solved the inequality below incorrectly. What mistake did she make?

-5x - 3.5 < 6.5

-5x < 10

x > 2

a She added 3.5 to both sides when she should have subtracted.

b She should have divided both sides by negative 5 as her first step.

c She should not have flipped the inequality symbol in her answer

d She should have divided 10 by negative 5 and gotten a -2

Given the inequality

-5x - 3.5 < 6.5

Step 1:

We will move -3.5 to the other side of the inequality to have:

-5x < 6.5+3.5

-5x<10

Step 2:

Divide both sides by the coefficient of x which is -5. Note that the inequality sign changes when dividing or multiplying both sides of an inequality with a negative value.

-5x/-5 > 10/-5

x > -2

Based on the calculation, Maria's mistake was that she should have divided 10 by negative 5 and gotten a -2 not 2.

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