document.write( "Question 762649: The number x=-2i is a zero of polynomial P(x)=x^4+2x^3+x^2+8x-12. Find all four zeros of this polynomial.\r
\n" ); document.write( "\n" ); document.write( "I have -3, -2, and 1 \n" ); document.write( "

Algebra.Com's Answer #464149 by josgarithmetic(39618) $\"\"$ $\"About$

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Your found root of -2 is wrong.\r
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\n" ); document.write( "\n" ); document.write( "You should find through Rational Roots Theorem and synthetic division, roots of -3, +1, and then you still would have a quadratic binomial of $\"%28x%5E2%2B4%29\"$ . Solving the equation $\"x%5E2%2B4=0\"$ for x will give you $\"-2i\"$ and $\"%2B2i\"$ \r
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\n" ); document.write( "\n" ); document.write( "Briefly, you should have made a process roughly equivalent to this:
\n" ); document.write( "Check for root -3;
\n" ); document.write( "Remainder 0, quotient $\"x%5E3-x%5E2%2B4x-4\"$
\n" ); document.write( "Check for root +1;
\n" ); document.write( "Remainder 0, quotient $\"x%5E2%2B4\"$
\n" ); document.write( "Solve the quadratic for its roots and find they are $\"-2i\"$ and $\"2i\"$ . \n" ); document.write( "

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