document.write( "Question 162632: How do you check your answer after simplifying a rational expression?
\n" ); document.write( "For example,\r
\n" ); document.write( "\n" ); document.write( "I took $\"%284x%5E2-+12x+%2B+9%29%2F%2810x%5E2+-+11x+-+6%29+\"$ and simplified it to
\n" ); document.write( " $\"%282x-3%29%2F%285x%2B2%29\"$ . However, the directions also want the answer to be checked but the book I give an example on how to check such a complex problem. I f you can show me how to go about checking the answer for this problem it would be helpful. \n" ); document.write( "

Algebra.Com's Answer #119853 by Edwin McCravy(20055) $\"\"$ $\"About$

You can put this solution on YOUR website!

\r\n" );
document.write( "Substitute a number for x in the original expression\r\n" );
document.write( "and then substitute it in the final answer and see if \r\n" );
document.write( "you get the same result.\r\n" );
document.write( "\r\n" );
document.write( "First substitute  in the original problem:\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "You could have done that in your head!\r\n" );
document.write( "\r\n" );
document.write( "Now substitute  in your final answer:\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "They're the same!  Both !\r\n" );
document.write( "You could have done that in your head, too.\r\n" );
document.write( "That's not a perfect check, but it is good\r\n" );
document.write( "evidence that it is correct.  [However, if \r\n" );
document.write( "you hadn't have gotten the same result you \r\n" );
document.write( "would have known for certain that your\r\n" );
document.write( "answer would have been wrong!]\r\n" );
document.write( "\r\n" );
document.write( "To be much surer, also substitute  \r\n" );
document.write( "in the original expression and also in the \r\n" );
document.write( "final answer. \r\n" );
document.write( "\r\n" );
document.write( "Substitute  in the original problem:\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "Now substitute  in your final answer:\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "\r\n" );
document.write( "They're the same!  Both !\r\n" );
document.write( "\r\n" );
document.write( "When both x=1 and x=0 give the same results when\r\n" );
document.write( "substituted in the original and in the final answer,\r\n" );
document.write( "then it is extremely likely that your answer is \r\n" );
document.write( "correct.  You can also substitute  or any \r\n" );
document.write( "other number you choose if you want to be absolutely \r\n" );
document.write( "sure!\r\n" );
document.write( "\r\n" );
document.write( "Edwin

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

\n" );