SOLUTION: Find all real and imaginary roots of: f(x) = x^3 - 2x - 4

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Question 1081493: Find all real and imaginary roots of: f(x) = x^3 - 2x - 4
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

x%5E3+-+2x+-+4+=0.....factor
x%5E3+%2B2x%5E2%2B2x-2x%5E2-4x+-+4+=0
%28x%5E3-2x%5E2%29%2B%282x%5E2-4x%29%2B%282x+-+4+%29=0
x%5E2%28x-2%29%2B2x%28x-2%29%2B2%28x+-+2+%29=0
%28x+-+2%29+%28x%5E2+%2B+2x+%2B+2%29+=+0
real solution:
if %28x+-+2%29+=+0=>x=2
imaginary solutions:
%28x%5E2+%2B+2x+%2B+2%29+=+0
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%28-2+%2B-+sqrt%282%5E2-4%2A1%2A2+%29%29%2F%282%2A1%29+
x+=+%28-2+%2B-+sqrt%284-8+%29%29%2F2+
x+=+%28-2+%2B-+sqrt%28-4+%29%29%2F2+
x+=+%28-2+%2B-+2i%29%2F2+
x+=+%28-cross%282%291+%2B-+cross%282%29i%29%2Fcross%282%291+
x+=+%28-1+%2B-+i%29+
x+=+-1+%2Bi+ or x+=+-1+-+i+