document.write( "Question 365323: Hi there, I have to find a degree 3 polynomial whose coefficients are real numbers and with given zeros: \"-3\", \"1-2i\"\r
\n" ); document.write( "\n" ); document.write( "If \"1-2i\" is a zero, then so is \"1%2B2i\" so then \"-3%281-2i%29%281%2B2i%29=+0\"\r
\n" ); document.write( "\n" ); document.write( "Then using another example, I came up with this equation. But I'll be honest I don't understand why/how I did this??\r
\n" ); document.write( "\n" ); document.write( "\"%28x-1%2B2i%29%28x-1-2i%29%28x%2B3%29\"\r
\n" ); document.write( "\n" ); document.write( "Then solving through...\r
\n" ); document.write( "\n" ); document.write( "\"x%5E2-x-2ix-x%2B1%2B2ix-2i%2B4i%5E2\"
\n" ); document.write( "\"%28x%5E2-2x%2B5%29%28x%2B3%29\"
\n" ); document.write( "\"x%5E3%2B3x%5E2-2x%5E2-6x%2B5x%2B15\"\r
\n" ); document.write( "\n" ); document.write( "which gives me my answer \"x%5E3%2Bx%5E2-x%2B15\", did I do this correctly?\r
\n" ); document.write( "\n" ); document.write( "Thanks so much for your time :)\r
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Algebra.Com's Answer #260433 by stanbon(75887)\"\" \"About 
You can put this solution on YOUR website!
find a degree 3 polynomial whose coefficients are real numbers and with given zeros: \"-3\", \"1-2i\"\r
\n" ); document.write( "\n" ); document.write( "If \"1-2i\" is a zero, then so is \"1%2B2i\" so then \"-3%281-2i%29%281%2B2i%29=+0\"
\n" ); document.write( "Comment: That is not true; it is not what \"zeroes\" mean.
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\n" ); document.write( "\n" ); document.write( "Then using another example, I came up with this equation. But I'll be honest I don't understand why/how I did this??
\n" ); document.write( "Comment: The rule is \"If a is a zero, (x-a) is a factor\"
\n" ); document.write( "--------\r
\n" ); document.write( "\n" ); document.write( "f(x) = (x-(1+2i))(x-(1-2i))(x--3)
\n" ); document.write( "---
\n" ); document.write( "Rearrange to get:
\n" ); document.write( "f(x) = ((x-1)-2i)((x-1)+2i)(x+3)
\n" ); document.write( "---
\n" ); document.write( "f(x) = [(x-1)^2 + 4][x+3]
\n" ); document.write( "---
\n" ); document.write( "f(x) = [x^2-2x+5][x+3]
\n" ); document.write( "---
\n" ); document.write( "f(x) = (x^2-2x+5)x + (x^2-2x+5)3
\n" ); document.write( "---
\n" ); document.write( "f(x) = x^3-2x^2+5x+3x^2-6x+15
\n" ); document.write( "---
\n" ); document.write( "f(x) = x^3+x^2-x+15
\n" ); document.write( "============================
\n" ); document.write( "You were correct.
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \r
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