document.write( "Question 1209146: Describe all solutions to z -3w - 2iw + 4iz = -8 where z and w are complex numbers. \n" ); document.write( "
Algebra.Com's Answer #847775 by greenestamps(13200)\"\" \"About 
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\n" ); document.write( "\"z+-3w+-+2iw+%2B+4iz+=+-8\"

\n" ); document.write( "Let z = a+bi
\n" ); document.write( "Let w = c+di

\n" ); document.write( "\"%28a%2Bbi%29-3%28c%2Bdi%29-2i%28c%2Bdi%29%2B4i%28a%2Bbi%29=-8\"

\n" ); document.write( "\"%281%2B4i%29%28a%2Bbi%29-%283%2B2i%29%28c%2Bdi%29=-8\"

\n" ); document.write( "\"%28a-4b-3c%2B2d%29%2B%284a%2Bb-2c-3d%29i=-8%2B0i\"

\n" ); document.write( "Equating the real and imaginary parts on both sides of the equation....

\n" ); document.write( "\"a-4b-3c%2B2d=-8\" and \"4a%2Bb-2c-3d=0\"

\n" ); document.write( "That's two equations in 4 unknowns. The best you can do is eliminate one variable to get a single (linear) equation in three unknowns, which will have an infinite number of solutions.

\n" ); document.write( "Solving the second equation for b and substituting in the first equation....

\n" ); document.write( "\"b=-4a%2B2c%2B3d\"

\n" ); document.write( "\"a-4%28-4a%2B2c%2B3d%29-3c%2B2d=-8\"

\n" ); document.write( "\"a%2B16a-8c-12d-3c%2B2d=-8\"

\n" ); document.write( "\"17a-11c-10d=-8\"

\n" ); document.write( "That last equation \"describes\" all the solutions to the given equation.

\n" ); document.write( "For one simple solution (undoubtedly the simplest), let b=d=0, making z=a and w=c:

\n" ); document.write( "\"a-3c=-8\"
\n" ); document.write( "\"4a-2c=0\"

\n" ); document.write( "Solve by elimination:

\n" ); document.write( "\"4a-2c=0\"
\n" ); document.write( "\"4a-12c=-32\"
\n" ); document.write( "\"10c=32\"
\n" ); document.write( "\"c=3.2\"
\n" ); document.write( "\"a-3%283.2%29=-8\"
\n" ); document.write( "\"a-9.6=-8\"
\n" ); document.write( "\"a=1.6\"

\n" ); document.write( "Simplest solution:
\n" ); document.write( "z = 1.6+0i
\n" ); document.write( "w = 3.2+0i

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