document.write( "Question 1210241: what two numbers multiply to -16 and add to 15
\n" ); document.write( " \n" ); document.write( "

Algebra.Com's Answer #851731 by ikleyn(52781) $\"\"$ $\"About$

You can put this solution on YOUR website!
.
\n" ); document.write( "what two numbers multiply to -16 and add to 15
\n" ); document.write( "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Answer. The numbers are 16 and -1.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Here are two ways to solve it.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "

\r\n" );
document.write( "First way is to guess it mentally. Usually, it requires several seconds and does not require writing.\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Another way is to introduce x for one number, 15-x for another number,\r\n" );
document.write( "and then to write and to solve this equation for the product \r\n" );
document.write( "\r\n" );
document.write( "    x*(15-x) = -16,\r\n" );
document.write( "\r\n" );
document.write( "    15x - x^2 = - 16,\r\n" );
document.write( "\r\n" );
document.write( "    x^2 - 15x - 16 = 0,\r\n" );
document.write( "\r\n" );
document.write( "    (x-16)*(x+1) = 0.      <<<---===  factoring\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "It gives the answer algebraically:  the numbers are 16 and -1.\r\n" );
document.write( "

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

\n" );