document.write( "Question 1056249: For the following problem, y varies inversely as the square of x.\r
\n" ); document.write( "\n" ); document.write( "If y = 81 when x = 9, find y when x is 3
\n" ); document.write( "

Algebra.Com's Answer #671412 by Edwin McCravy(20060)\"\" \"About 
You can put this solution on YOUR website!
y varies inversely as the square of x.
\n" ); document.write( "
\r\n" );
document.write( "\"y\"\"%22%22=%22%22\"\"k%2Fx%5E2\"\r\n" );
document.write( "

\n" ); document.write( "If y = 81 when x = 9,
\n" ); document.write( "
\r\n" );
document.write( "Substitute that in\r\n" );
document.write( "\r\n" );
document.write( "\"81\"\"%22%22=%22%22\"\"k%2F9%5E2\"\r\n" );
document.write( "\r\n" );
document.write( "Solve for k\r\n" );
document.write( "\r\n" );
document.write( "\"81\"\"%22%22=%22%22\"\"k%2F81\"\r\n" );
document.write( "\r\n" );
document.write( "Multiply both sides by 81\r\n" );
document.write( "\r\n" );
document.write( "\"6561\"\"%22%22=%22%22\"\"k\"\r\n" );
document.write( "\r\n" );
document.write( "Substitute that in \r\n" );
document.write( "\r\n" );
document.write( "\"y\"\"%22%22=%22%22\"\"k%2Fx%5E2\"\r\n" );
document.write( "\r\n" );
document.write( "\"y\"\"%22%22=%22%22\"\"6561%2Fx%5E2\"  <-- that's the formula\r\n" );
document.write( "

\n" ); document.write( "find y when x is 3
\n" ); document.write( "
\r\n" );
document.write( "Substitute 3 for x\r\n" );
document.write( "\r\n" );
document.write( "\"y\"\"%22%22=%22%22\"\"6561%2F3%5E2\"\r\n" );
document.write( "\r\n" );
document.write( "\"y\"\"%22%22=%22%22\"\"6561%2F9\"\r\n" );
document.write( "\r\n" );
document.write( "\"y\"\"%22%22=%22%22\"\"729\"\r\n" );
document.write( "\r\n" );
document.write( "Edwin
\n" ); document.write( "
\n" );