document.write( "Question 632148: Solve.\r
\n" ); document.write( "\n" ); document.write( "w^4-20w^2-2=0\r
\n" ); document.write( "\n" ); document.write( "What is the solution? \n" ); document.write( "
Algebra.Com's Answer #398047 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
Let \"+w%5E4+=+z%5E2+\"
\n" ); document.write( "\"+z+=+w%5E2+\" and
\n" ); document.write( "\"+z+=+-w%5E2+\"\r
\n" ); document.write( "\n" ); document.write( "\"+w%5E4+-+20w%5E2+-+2+=+0++\"
\n" ); document.write( "\"+z%5E2+-+20z++-+2+=+0+\"
\n" ); document.write( "\"+z%5E2+-+20z+=+2+\"
\n" ); document.write( "Complete the square
\n" ); document.write( "\"+z%5E2+-+20z+%2B+%28-20%2F2%29%5E2+=+2+%2B+%28-20%2F2%29%5E2+\"
\n" ); document.write( "\"+z%5E2+-+20z+%2B+100++=+2+%2B+100+\"
\n" ); document.write( "\"+%28+z+-+10+%29%5E2+=+102+\"
\n" ); document.write( "Take the square root of both sides
\n" ); document.write( "\"+z+-+10+=+sqrt%28102%29+\"
\n" ); document.write( "\"+z+=+10+%2B+sqrt%28+102+%29+\"
\n" ); document.write( "and
\n" ); document.write( "\"+z+=+10+-+sqrt%28+102+%29+\"
\n" ); document.write( "----------------------
\n" ); document.write( "\"+w%5E2+=+10+%2B+sqrt%28+102+%29+\"
\n" ); document.write( "\"+w+=+sqrt%28+10+%2B+sqrt%28102%29+%29+\"
\n" ); document.write( "\"+w+=+-sqrt%28+10+%2B+sqrt%28102%29+%29+\"
\n" ); document.write( "-----------------------
\n" ); document.write( "\"+w%5E2+=+10+-+sqrt%28102%29+\"
\n" ); document.write( "\"+w+=+sqrt%28+10+-+sqrt%28102%29+%29+\"
\n" ); document.write( "\"+w+=+-sqrt%28+10+-+sqrt%28102%29+%29+\"
\n" ); document.write( "-----------------------
\n" ); document.write( "These are the 4 roots
\n" ); document.write( "Here's a plot of the equation:
\n" ); document.write( "\"+graph%28+400%2C+400%2C+-8%2C+8%2C+-120%2C+20%2C+x%5E4+-+20x%5E2+-+2+%29+\"
\n" ); document.write( "There are 2 real roots and 2 imaginary, which
\n" ); document.write( "seems to agree with the plot\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "
\n" );