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?

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?

sooobored · Answer

when dividing by a negative number to both sides, you need to switch the sign from < to > and viceversa

helper101 · Answer

its C

sooobored · Answer

ex. 
-1> -9
if we divide or multiply by -1 to both sides with out changing the sign

1>9
this is not true
1<9 is true