(01.01) Kisha and Rae are asked to solve −5x − 14 = 2x + 7. Identify where one of them made an error.


Kisha


−5x − 14 = 2x + 7

−5x − 14 − 2x = 2x + 7 − 2x

−7x − 14 = 7

−7x − 14 + 14 = 7 + 14

−7x = 21

Negative 7x over negative 7 equals 21 over negative 7

x = − 3



Rae

−5x − 14 = 2x + 7

−5x − 14 + 5x = 2x + 7 + 5x

−14 = 7x + 7

−14 + 7 = 7x + 7 + 7

−7 = 7x

negative 7 over 7 equals 7x over 7

x = − 1
Rae made the error when she added 7 
Rae made the error when she added 5x 
Kisha made the error when she subtracted 2x 
Kisha made the error when she divided by −7