First, subtract 42 from both sides:
[tex]3w^2 = -36[/tex]
Isolate w:
[tex]w^2 = \frac{-36}{3} [/tex]
[tex]w^2 = -12[/tex]
Solve for w:
[tex]w = + \sqrt{-12} = 2i \sqrt{3} [/tex]
and
[tex]w = - \sqrt{-12} = -2i \sqrt{3} [/tex]
So your answers are above.
