Kelly is trying to work out the two values of w for which 3w-w^3=2. Her values are 1 and -1. Are her values correct?

Sub in her values to see if the LHS and the RHS of the equation equate:

w=1:  3(1)-(1)^3=2  >>>  3-1=2  >>>  2=2  ✅

Therefore 1 is a correct value.

w=-1: 3(-1)-(-1)^3=2  >>>  -3+1=2  >>>  -2=2  ❎

Therefore -1 is not a correct value.