document.write( "Question 79700: To solve 1/x-3+ 1/x+3 = 10/x^2-9, which step would result?\r
\n" ); document.write( "\n" ); document.write( "I got: (x+3)+(x+3) = 10\r
\n" ); document.write( "\n" ); document.write( "Is this correct?
\n" ); document.write( "Thanks~
\n" ); document.write( "

Algebra.Com's Answer #57206 by bucky(2189)\"\" \"About 
You can put this solution on YOUR website!
Given:
\n" ); document.write( ".
\n" ); document.write( "\"1%2F%28x-3%29+%2B++1%2F%28x%2B3%29+=+10%2F%28x%5E2-9%29\"
\n" ); document.write( ".
\n" ); document.write( "Don't think you are correct, but let's check your answer. You got:
\n" ); document.write( ".
\n" ); document.write( "\"%28x%2B3%29%2B%28x%2B3%29+=+10\"
\n" ); document.write( ".
\n" ); document.write( "Remove the parentheses and this becomes:
\n" ); document.write( ".
\n" ); document.write( "\"x+%2B+3++%2B+x+%2B+3+=+10\"
\n" ); document.write( ".
\n" ); document.write( "Add like terms on the left side and you get:
\n" ); document.write( ".
\n" ); document.write( "\"2x+%2B+6+=+10\"
\n" ); document.write( ".
\n" ); document.write( "Subtract 6 from both sides and you get:
\n" ); document.write( ".
\n" ); document.write( "\"2x+=+4\"
\n" ); document.write( ".
\n" ); document.write( "Then divide both sides by 2 and you finally have \"x+=+2\". If you return to the
\n" ); document.write( "original equation and substitute 2 for x it becomes:
\n" ); document.write( ".
\n" ); document.write( "\"1%2F%282-3%29%2B1%2F%282%2B3%29+=+10%2F%282%5E2+-9%29\"
\n" ); document.write( ".
\n" ); document.write( "Doing the math in the 3 denominators results in:
\n" ); document.write( ".
\n" ); document.write( "\"1%2F%28-1%29+%2B+1%2F5+=+10%2F%284-9%29\"
\n" ); document.write( ".
\n" ); document.write( "and this further simplifies to:
\n" ); document.write( ".
\n" ); document.write( "\"-1+%2B++1%2F5+=+10%2F-5\"
\n" ); document.write( ".
\n" ); document.write( "which becomes:
\n" ); document.write( ".
\n" ); document.write( "\"-1+%2B+1%2F5+=+-2\"
\n" ); document.write( ".
\n" ); document.write( "by adding +1 to both sides this becomes:
\n" ); document.write( ".
\n" ); document.write( "\"%2B1%2F5+=+-1\"
\n" ); document.write( ".
\n" ); document.write( "That doesn't look too good.
\n" ); document.write( ".
\n" ); document.write( "Let's go back to the original problem and work it out:
\n" ); document.write( ".
\n" ); document.write( "\"1%2F%28x-3%29+%2B++1%2F%28x%2B3%29+=+10%2F%28x%5E2-9%29\"
\n" ); document.write( ".
\n" ); document.write( "You probably recognized that the denominator on the right side factors to:
\n" ); document.write( ".
\n" ); document.write( "\"%28x-3%29%2A%28x%2B3%29\"
\n" ); document.write( ".
\n" ); document.write( "Substitute that into the equation and it becomes:
\n" ); document.write( ".
\n" ); document.write( "\"1%2F%28x-3%29+%2B++1%2F%28x%2B3%29+=+10%2F%28%28x-3%29%28x%2B3%29%29\"
\n" ); document.write( ".
\n" ); document.write( "Now multiply all the terms on both sides by \"%28x-3%29%28x%2B3%29\". When you do it becomes:
\n" ); document.write( ".
\n" ); document.write( "
\n" ); document.write( ".
\n" ); document.write( "cross out the common terms in the denominator and the numerator:
\n" ); document.write( ".\r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( ".
\n" ); document.write( "and the equation becomes:
\n" ); document.write( ".\r
\n" ); document.write( "\n" ); document.write( "\"%28x%2B3%29+%2B+%28x-3%29+=+10\"
\n" ); document.write( ".
\n" ); document.write( "Remove the parentheses:
\n" ); document.write( ".
\n" ); document.write( "\"x+%2B+3+%2B+x+-+3+=+10\"
\n" ); document.write( ".
\n" ); document.write( "Combine the like terms on the left side (note +3 -3 = 0) and you get:
\n" ); document.write( ".
\n" ); document.write( "\"2x+=+10\"
\n" ); document.write( ".
\n" ); document.write( "Finally divide both sides by 2 and you get:
\n" ); document.write( ".
\n" ); document.write( "\"x+=+5\"
\n" ); document.write( ".
\n" ); document.write( "Now let's check the answer. Return to the original equation and substitute 5 for x to get:
\n" ); document.write( ".
\n" ); document.write( "\"1%2F%28x-3%29+%2B++1%2F%28x%2B3%29+=+10%2F%28x%5E2-9%29\"
\n" ); document.write( ".
\n" ); document.write( "\"1%2F%285-3%29+%2B++1%2F%285%2B3%29+=+10%2F%285%5E2-9%29\"
\n" ); document.write( ".
\n" ); document.write( "\"1%2F2+%2B+1%2F8+=+10%2F%2825-9%29\"
\n" ); document.write( ".
\n" ); document.write( "\"4%2F8+%2B+1%2F8+=+10%2F16\"
\n" ); document.write( ".
\n" ); document.write( "\"5%2F8+=+10%2F16\"
\n" ); document.write( ".
\n" ); document.write( "\"5%2F8+=+5%2F8\"
\n" ); document.write( ".
\n" ); document.write( "That works ... so the answer is x = 5
\n" ); document.write( ".
\n" ); document.write( "Hope this helps you to find your mistake.
\n" ); document.write( "
\n" );