Andrew solved the following inequality, and his work is shown below:

−4(x + 8) + 25 ≤ −2 + 1(x − 50)
−4x − 32 + 25 ≤ −2 + 1x − 50
−4x − 7 ≤ 1x − 52
−5x ≤ −45
x ≤9

What mistake did Andrew make in solving the inequality?

He subtracted 1x from both sides when he should have added 4x.

When dividing by −5, he did not change the ≤ to ≥.

He added 7 to both sides when he should have added 52.

He did not make a mistake.

Question

Andrew solved the following inequality, and his work is shown below:

−4(x + 8) + 25 ≤ −2 + 1(x − 50)
−4x − 32 + 25 ≤ −2 + 1x − 50
−4x − 7 ≤ 1x − 52
−5x ≤ −45
x ≤9

What mistake did Andrew make in solving the inequality?

 He subtracted 1x from both sides when he should have added 4x.

 When dividing by −5, he did not change the ≤ to ≥.

 He added 7 to both sides when he should have added 52.

 He did not make a mistake.

radar · Answer

Andrew did not follow the rule when dividing or multiplying and inequality by a negative number.  Are you familiar with the rule?

kidthatbro8 · Answer

i don't know, this question is confusing.

radar · Answer

Look closely at the last two lines, note that Andrew is dividing by a -5.

kidthatbro8 · Answer

oh ! the one where he is supposed to flip the sign ?

radar · Answer

What must he do to the inequality sign?  Yes, you got it.

kidthatbro8 · Answer

ah, thank you.