document.write( "Question 26803: find a third-degree polynomial equation with rational coefficients that has the roots -5 and 4+i \n" ); document.write( "
Algebra.Com's Answer #14602 by venugopalramana(3286)\"\" \"About 
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find a third-degree polynomial equation with rational coefficients that has the roots -5 and 4+i
\n" ); document.write( "IF THE COEFFICIENTS OF POLYNOMIAL ARE REAL ,THEN COMPLEX ROOTS CAN OCCUR ONLY IN CONJUGATES.SO IF 4+I IS A ROOT THEN 4-I IS ALSO A ROOT.SO,WE HAVE ALL THE 3 ROOTS FOR THE 3 RD. DEGREE POLYNOMIAL...HENCE THE POLYNOMIAL IS GIVEN BY...
\n" ); document.write( "(X+5)(X-(4+I))((X-(4-I))=0
\n" ); document.write( "(X+5){(X-4)^2-I^2}=0
\n" ); document.write( "(X+5)(X^2+16-8X+1)=0
\n" ); document.write( "=(X+5)(X^2-8X+17)=0
\n" ); document.write( "=X^3-8X^2+17X+5X^2-40X+85=0
\n" ); document.write( "=X^3-3X^2-23X+85=0
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