document.write( "Question 175737: find the real number solutions of the equation.\r
\n" ); document.write( "\n" ); document.write( "y^4-14y^2+45
\n" ); document.write( "

Algebra.Com's Answer #130828 by solver91311(24713)\"\" \"About 
You can put this solution on YOUR website!
Your first problem is that you don't actually have an equation. There is not an equal sign to be seen anywhere in \"y%5E4-14y%5E2%2B45\". So all I can do is assume that you meant \"y%5E4+-+14y%5E2+%2B+45+=+0\". Presuming this is the case, let \"t+=+y%5E2\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Then you can write: \"t%5E2+-+14t+%2B+45+=+0\" which is a quadratic that can be solved by ordinary means; this one factors because \"+%28-5%29+%2A+%28-9%29+=+45\" and \"%28-5%29+%2B+%28-9%29+=+-14\", so:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"t%5E2+-+14t+%2B+45+=+%28t+-+5%29%28t+-+9%29+=+0\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Therefore, \"t+-+5+=+0\" or \"t+-+9+=+0\" which is to say:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"t+=+5\" or \"t+=+9\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "But remember that \"t+=+y%5E2\", so we can now say:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y%5E2+=+5\" which means that \"y+=+sqrt%285%29\" or \"y+=+-sqrt%285%29\", and\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"y%5E2+=+9\" which means that \"y+=+sqrt%289%29+=+3\" or \"y+=+-sqrt%289%29+=+-3\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "And there are your four real number roots.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );