document.write( "Question 1058617: How do I right this word problem as a rational equation?
\n" ); document.write( "Marty drove his fully loaded moving van to Memphis. With his van empty, Marty drove 15 mi/h faster and made the return trip in 1.5 hours less. Find the speed going to Memphis. \n" ); document.write( "

Algebra.Com's Answer #673706 by josgarithmetic(39617) $\"\"$ $\"About$

You can put this solution on YOUR website!
The description is constant travel rates problem, and not necessarily a rational equations problem.\r
\n" ); document.write( "\n" ); document.write( "

\r\n" );
document.write( "             SPEED        TIME      DISTANCE\r\n" );
document.write( "\r\n" );
document.write( "LOADED       r             t          d\r\n" );
document.write( "\r\n" );
document.write( "EMPTY       r+15          t-1.5       d\r\n" );
document.write( "\r\n" );
document.write( "TOTAL\r\n" );
document.write( "

\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " $\"system%28rt=d%2C%28r%2B15%29%28t-1.5%29=d%29\"$ \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " $\"t=d%2Fr\"$
\n" ); document.write( "-
\n" ); document.write( " $\"%28r%2B15%29%28%28d%2Fr%29-1.5%29=d\"$
\n" ); document.write( " $\"r%28r%2B15%29%28d%2Fr-1.5%29=d\"$
\n" ); document.write( " $\"%28r%2B15%29%28d-1.5r%29=d\"$
\n" ); document.write( " $\"rd%2B15d-1.5r%5E2-%2815%29%281.5%29r=d\"$
\n" ); document.write( " $\"rd%2B14d-1.5r%5E2-22.5r=0\"$
\n" ); document.write( " $\"-rd-14d%2B1.5r%5E2%2B22.5r=0\"$
\n" ); document.write( " $\"1.5r%5E2-rd%2B22.5r-14d=0\"$
\n" ); document.write( " $\"1.5r%5E2%2B%2822.5-d%29r-14d=0\"$ -----quadratic equation in r, but also d is still unknown variable.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " $\"r=%28d-22.5%2B-+sqrt%28%2822.5-d%29%5E2-4%2A1.5%2A%28-14d%29%29%29%2F3\"$ \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " $\"r=%28d-22.5%2B-+sqrt%28%2822.5-d%29%5E2%2B84d%29%29%2F3\"$ \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " $\"r=%28d-22.5%2B-+sqrt%28506.25-45d%2Bd%5E2%2B84d%29%29%2F3\"$ \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( " $\"highlight%28r=%28d-22.5%2B-+sqrt%28d%5E2%2B39d%2B506.25%29%29%2F3%29\"$
\n" ); document.write( "The discriminant is not a perfect square, and you do not have enough information described to know the value of d.
\n" ); document.write( "This is all that can be done. \n" ); document.write( "

\n" );