Question

Sam solved the following problem:

-4x + 5 > 29
-4x + 5 - 5 > 29 - 5
-4x > -24
-4x/-4 > -24/-4
x > 6

What were his two mistakes?

Answer 1

Sam subtracted wrong. it should be 29 - 5 = 24, not - 24.

When dividing by a negative, in an inequality, you must flip the sign. Sam did not flip his sign when dividing by -4.

Explanation:

the answer should be x < -6

Answer 2

Sam made it -24 versus 24 (29-5=24 not -24)

(Sam failed to flip the inequality)

Explanation:

-4x + 5 > 29

Subtract 5 from each side

-4x+5-5 > 29-5

-4x > 24 Sam made it -24 versus 24 (29-5=24 not -24)

Divide by -4 Remember to flip the inequality

-4x/-4 < 24/-4 (Sam failed to flip the inequality)

x < -6