document.write( "Question 1181502: What are the roots of (z^2) - z(1 + i) + 5i = 0? \n" ); document.write( "
Algebra.Com's Answer #811406 by MathLover1(20849)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "roots of \r
\n" ); document.write( "\n" ); document.write( "\"z%5E2+-+z%281+%2B+i%29+%2B+5i+=+0\"......... substitute \"z=x%2Byi\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%2Byi%29%5E2+-+%28x%2Byi%29%281+%2B+i%29+%2B+5i+=+0\"...expand\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2B2xy%2Ai%2B%28yi%29%5E2+-+%28x%2Bx%2Ai%2Byi%2By%2Ai%5E2%29%2B+5i+=+0\"\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2B2xy%2Ai%2B%28yi%29%5E2+-+%28x%2Bx%2Ai%2Byi-y%29%2B+5i+=+0\"\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2B2xy%2Ai%2B%28y%5E2i%5E2%29+-+x-x%2Ai-yi%2By%2B+5i+=+0\"\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2%2B2xy%2Ai-y%5E2+-+x-x%2Ai-yi%2By%2B+5i+=+0\"...........combine real parts and imaginary parts\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%5E2-y%5E2+-x%2By%29%2B2xy%2Ai-x%2Ai-yi%2B+5i=0\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%5E2-y%5E2+-x%2By%29-i%282xy-x-y%2B5%29=0\"\r
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\n" ); document.write( "\n" ); document.write( "Complex numbers can be equal only if their real and imaginary parts are equal.\r
\n" ); document.write( "\n" ); document.write( "\"x%5E2-y%5E2+-x%2By=0\".....eq.1
\n" ); document.write( "\"2xy-x-y%2B5=0\".....eq.2
\n" ); document.write( "-------------------solve this system \r
\n" ); document.write( "\n" ); document.write( "\"2xy-x=y-5\"....eq.2, solve for \"x\"\r
\n" ); document.write( "\n" ); document.write( "\"%282y-1%29x=y-5\"\r
\n" ); document.write( "\n" ); document.write( "\"x=%28y-5%29%2F%282y-1%29\"\r
\n" ); document.write( "\n" ); document.write( "substitute in eq.1\r
\n" ); document.write( "\n" ); document.write( "\"%28%28y-5%29%2F%282y-1%29%29%5E2-y%5E2+-%28y-5%29%2F%282y-1%29%2By=0\"\r
\n" ); document.write( "\n" ); document.write( "\"%28%28y+-+2%29+%28y+%2B+1%29%29%2F%282+y+-+1%29+=+0\"} .........zeros are in numerator\r
\n" ); document.write( "\n" ); document.write( "\"%28y+-+2%29+%28y+%2B+1%29=0\"\r
\n" ); document.write( "\n" ); document.write( "\"y=2+\"or \"y=-1\"\r
\n" ); document.write( "\n" ); document.write( "then\r
\n" ); document.write( "\n" ); document.write( "\"x=%282-5%29%2F%282%2A2-1%29=-3%2F3=-1\"\r
\n" ); document.write( "\n" ); document.write( "\"x=%28-1-5%29%2F%282%28-1%29-1%29=-6%2F-3=2\"\r
\n" ); document.write( "\n" ); document.write( "solutions:\r
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\n" ); document.write( "\n" ); document.write( "\"x=2\", \"y=-1\"
\n" ); document.write( "or
\n" ); document.write( "\"x=-1\", \"y=2\"\r
\n" ); document.write( "\n" ); document.write( "Substitute back \"z=x%2Byi\", and roots are\r
\n" ); document.write( "\n" ); document.write( "\"z%5B1%5D=2-i\"
\n" ); document.write( "\"z%5B2%5D=-1%2B2i\"\r
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