Question

Anna and Belle are asked to solve −2x − 15 = 6x + 9. Identify where one of them made an error.AnnaBelle−2x − 15 = 6x + 9−2x − 15 −6x = 6x + 9 −6x
−8x − 15 = 9
−8x − 15 + 15 = 9 + 15
−8x = 24
Negative 8x over negative 8 equals 24 over negative 8
x = −3
−2x − 15 = 6x + 9
−2x − 15 + 2x = 6x + 9 + 2x
−15 = 8x + 9
−15 + 9 = 8x + 9 + 9
−6 = 8x
Negative 8x over negative 8 equals 24 over negative 8
Negative two-thirds
Anna made the error when she subtracted 6x.
Anna made the error when she divided by −8.
Belle made the error when she added 2x.
Belle made the error when she added 9.