SOLUTION: I'm having problems figuring out what this answer is using complex numbers. Please help! Solve in the complex number system. 8x^3 + 27 = 0

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Question 65224: I'm having problems figuring out what this answer is using complex numbers. Please help! Solve in the complex number system. 8x^3 + 27 = 0
Answer by venugopalramana(3286) About Me  (Show Source):
You can put this solution on YOUR website!
I'm having problems figuring out what this answer is using complex numbers. Please help! Solve in the complex number system. 8x^3 + 27 = 0
use formula
a^3+b^3=(a+b)(a^2-ab+b^2)
(2x)^3+(3)^3=[2x+3][(2x)^2-(2x)(3)+3^2]=0
=(2x+3)[4x^2-6x+9]=0
hence 2x+3=0....or......x=-3/2......or
4x^2-6x+9=0
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%286+%2B-+sqrt%28+6%5E2-4%2A4%2A9+%29%29%2F%282%2A4%29+
x+=+%286+%2B-+sqrt%28+36-144+%29%29%2F%288%29+
x+=+%286+%2B-+sqrt%28+-108+%29%29%2F%288%29+
x+=+%283+%2B-+3sqrt%28+-3+%29%29%2F%284%29+
x = [3+3isqrt(3)]/4 or [3-3isqrt(3)]/4