Finding roots of complex polynomial with conjugates

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I am having problem with the following question... I know that I should use De Moivre's formula somewhere... but can't quite get to it $$ (-15w + 34\bar{w})^4 = -1 $$

will be happy to get some help, Thanks!

Ron

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Let $w=a+ib\iff \bar w$

$$(19a-49ib)^4=1=e^{2n\pi i}$$ where $n$ is any integer

$19a+(-49b)i=e^{\dfrac{2n\pi i}4}$ where $n\equiv0,1,2,3\pmod4$

Now for each case, equate the real & the imaginary parts