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

-5 (x + 4) + 21 ≥ - 3 + 4 (x - 8)

-5x - 20 + 21 ≥ - 3 + 4x - 32

-5x + 1 ≥ 4x - 35

-9x ≥ - 36

x ≥ 4

What mistake did Eduardo make in solving the inequality?

When dividing by - 9, he did not change the ≥ to ≤.

He subtracted 4x from both sides when he should have added 5x.

He subtracted 1 from both sides when he should have added 36.

He did not make a mistake.

Question

Mathematics

Shea Nguyen

4 April, 20:05

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

-5 (x + 4) + 21 ≥ - 3 + 4 (x - 8)

-5x - 20 + 21 ≥ - 3 + 4x - 32

-5x + 1 ≥ 4x - 35

-9x ≥ - 36

x ≥ 4

What mistake did Eduardo make in solving the inequality?

When dividing by - 9, he did not change the ≥ to ≤.

He subtracted 4x from both sides when he should have added 5x.

He subtracted 1 from both sides when he should have added 36.

He did not make a mistake.

+3

Answers (2)

Know the Answer?

Angel Bruce · Answer 1

"when dividing by - 9, he did not change the ≥ to ≤."

Villanueva · Answer 2

It's "w hen dividing by - 9, he did not change the ≥ to ≤."

Whenever you multiply or divide by a negative, the sign always flips to the opposite way.