document.write( "Question 771962: Hello, can you please show me how to do the work for this question: What is the center for the circle represented by the equation x^2+y^2-4x+2y-4=0? \n" ); document.write( "

Algebra.Com's Answer #470600 by MathLover1(20850) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"x%5E2%2By%5E2-4x%2B2y-4=0\"$ \r
\n" ); document.write( "\n" ); document.write( "write it first in the standard form: $\"%28x+-+h%29%5E2+%2B+%28y-k%29%5E2+=+r%5E2\"$ where $\"h\"$ is x-coordinate and $\"k\"$ is y-coordinate of the center ( $\"h\"$ , $\"k\"$ ) and $\"r\"$ is a radius\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " $\"%28x%5E2-4x%29%2B%28y%5E2%2B2y%29=4\"$ ...complete square\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " $\"%28x%5E2-4x%2B_%29%2B%28y%5E2%2B2y%2B_%29=4\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"%28x%5E2-4x%2B4%29-4%2B%28y%5E2%2B2y%2B1%29-1=4\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"%28x-2%29%5E2%2B%28y%2B1%29%5E2-5=4\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"%28x-2%29%5E2%2B%28y%2B1%29%5E2=9+\"$ \r
\n" ); document.write( "\n" ); document.write( "so, the center is at ( $\"h\"$ , $\"k\"$ )=( $\"2\"$ , $\"-1\"$ )\r
\n" ); document.write( "\n" ); document.write( "and radius $\"r=3\"$ \r
\n" ); document.write( "\n" ); document.write( "

\r
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "

\n" );