document.write( "Question 171090: 2=-9x^2 - x \n" ); document.write( "
Algebra.Com's Answer #126317 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!

\n" ); document.write( "\"2=-9x%5E2-x\" Start with the given equation.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"2%2B9x%5E2%2B1x=0\" Get all terms to the left side.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"9x%5E2%2Bx%2B2=0\" Rearrange the terms.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Notice we have a quadratic equation in the form of \"ax%5E2%2Bbx%2Bc\" where \"a=9\", \"b=1\", and \"c=2\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Let's use the quadratic formula to solve for x\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x+=+%28-b+%2B-+sqrt%28+b%5E2-4ac+%29%29%2F%282a%29\" Start with the quadratic formula\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x+=+%28-%281%29+%2B-+sqrt%28+%281%29%5E2-4%289%29%282%29+%29%29%2F%282%289%29%29\" Plug in \"a=9\", \"b=1\", and \"c=2\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x+=+%28-1+%2B-+sqrt%28+1-4%289%29%282%29+%29%29%2F%282%289%29%29\" Square \"1\" to get \"1\". \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x+=+%28-1+%2B-+sqrt%28+1-72+%29%29%2F%282%289%29%29\" Multiply \"4%289%29%282%29\" to get \"72\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x+=+%28-1+%2B-+sqrt%28+-71+%29%29%2F%282%289%29%29\" Subtract \"72\" from \"1\" to get \"-71\"\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x+=+%28-1+%2B-+sqrt%28+-71+%29%29%2F%2818%29\" Multiply \"2\" and \"9\" to get \"18\". \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x+=+%28-1+%2B-+i%2Asqrt%2871%29%29%2F%2818%29\" Simplify the square root (note: If you need help with simplifying square roots, check out this solver) \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "\"x+=+%28-1%2Bi%2Asqrt%2871%29%29%2F%2818%29\" or \"x+=+%28-1-i%2Asqrt%2871%29%29%2F%2818%29\" Break up the expression. \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "So the answers are \"x+=+%28-1%2Bi%2Asqrt%2871%29%29%2F%2818%29\" or \"x+=+%28-1-i%2Asqrt%2871%29%29%2F%2818%29\" \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "which approximate to \"x=-0.556%2B0.468%2Ai\" or \"x=-0.5556-0.468%2Ai\"
\n" ); document.write( "
\n" ); document.write( "
\n" );