HUGE FAN IF YOU ANSWER!

Marcie solved the following inequality, and her work is shown below:

−2(x − 5) − 12 ≤ 4 + 6(x + 3)
−2x + 10 − 12 ≤ 4 + 6x + 18
−2x − 2 ≤ 6x + 22
−8x ≤ 24
x ≤ −3

What mistake did Marcie make in solving the inequality?

Question

HUGE FAN IF YOU ANSWER!

Marcie solved the following inequality, and her work is shown below:

−2(x − 5) − 12 ≤ 4 + 6(x + 3)
−2x + 10 − 12 ≤ 4 + 6x + 18
−2x − 2 ≤ 6x + 22
−8x ≤ 24
x ≤ −3

What mistake did Marcie make in solving the inequality?

michele_laino · Answer

in the last step Marcie has divided the inequality by -8, nevertheless, when you divide an inequality by a negative number the sense of inequality change, so the right answer is:
$$x \ge -3$$