document.write( "Question 218142: what are the zeros for f(x)=x^4-x^3+3x^2-9x-54 \n" ); document.write( "
Algebra.Com's Answer #164365 by RAY100(1637)![]() ![]() ![]() You can put this solution on YOUR website! f(x)= x^4 -x^3 +3x^2 -9x -54 \n" ); document.write( ". \n" ); document.write( "zeros =p/q= (factors of constant)/ (factors of leading coeff)= +/- 54/1 \n" ); document.write( ". \n" ); document.write( "or zeroes are factors of 54,,,+/- 1,54,2,27,3,18,6,9 \n" ); document.write( ". \n" ); document.write( "If we plot using a graphing calc, we find zero's at x=-2,,,x=+3 \n" ); document.write( ". \n" ); document.write( "using synthetic division to confirm,, and find imaginary zeros \n" ); document.write( ". \n" ); document.write( ".try x=3 \n" ); document.write( ". \n" ); document.write( ".,,,,,3|,,,1,,,-1,,,3,,,-9,,,-54 \n" ); document.write( ".,,,,,,,,,,,,,,3,,,,6,,,,27,,+54 \n" ); document.write( ".,,,,,,,------------------------ \n" ); document.write( ".,,,,,,,,,,1,,,2,,,,9,,,18,,,,0,,,ok,,,,now try x=-2 \n" ); document.write( ". \n" ); document.write( ",,,,,,-2|,,1,,,2,,,,9,,,18 \n" ); document.write( ".,,,,,,,,,,,,,,-2,,,0,,,-18 \n" ); document.write( ",,,,,,,,--------------------- \n" ); document.write( ",,,,,,,,,,,1,,,0,,,,9,,,,,0,,,,,,,,ok \n" ); document.write( ". \n" ); document.write( "Remainder is ,,1x^2 +0x +9 \n" ); document.write( ". \n" ); document.write( ".This factors to (x+3i)(x-3i),,,,,imaginary zeros,,,(use quadratic formula if you don't remember) \n" ); document.write( ". \n" ); document.write( "Set of zeros is,,,,x=3,,,x=-2,,,x=+3i,,,,x=-3i \n" ); document.write( ". \n" ); document.write( ". \n" ); document.write( "this can be confirmed by multiplying above to get original \n" ); document.write( ". \n" ); document.write( "check ,,,,(x^2 +9) (x+2)(x-3) = (x^3 +2x^2 +9x +18)(x-3) = x^4 -x^3 +3x^2 =9x -54,,,,,ok \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( " |