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?
Please include steps as simple as you can

Answer 1

those ???? are - signs

Answer 2

Ellen made the mistake of not flipping sign.

Answer 3

Eduardo*

Answer 4

lol thx :)

Answer 5

he messed up on the very last step....when dividing/multiplying an inequality by a negative, it changes the sign
answer is : x <= 4

Answer 6

:D