Question

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? (2 points)

Answer 1

should be x ≤ 4

Explanation:

Answer 2

the comparison was not reversed when dividing by -9

Explanation:

It looks like Eduardo's steps might be ...

−5(x + 4) + 21 ≥ −3 + 4(x − 8)

−5x − 20 + 21 ≥ −3 + 4x − 32 . . . . correct

−5x + 1 ≥ 4x − 35 . . . . correct

−9x ≥ −36 . . . . correct

x ≥ 4 . . . . . should be x ≤ 4

Dividing by -9 should reverse the comparison symbol.