Question

Describe and correct the error in finding the difference.
(4m + 9) − 3(2m − 5) = 4m + 9 − 6m − 15
= 4m − 6m + 9 − 15
= −2m − 6

Answer 1

1. in the distributive -3(2m - 5), one forget to use the positive sign instead of the negative sign.

2. the answer should be -2m + 24

Answer 2

final answer should be - 2m + 24

(4m + 9) - 3(2m - 5 ) → (distributing gives)

4m + 9 - 6m + 15 → ( error in original has - 15 )

collect like terms

(4m - 6m ) + (9 + 15) = - 2m + 24