document.write( "Question 638414: Rational Equations. Solve the equation.\r
\n" ); document.write( "\n" ); document.write( "(2x-9)/(x-7)+x/2=5/(x-7)
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Algebra.Com's Answer #402177 by josh_jordan(263)\"\" \"About 
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to solve for x, you will first need to find the LCD of the fractions involved. Let's look at the denominators: x - 7, 2, x - 7. The LCD of these fractions is 2(x - 7). We will then multiply each fraction by \"2%28x+-+7%29\":\r
\n" ); document.write( "\n" ); document.write( "\"%28%282x-9%29%2A2%28x-7%29%29%2F%28x-7%29%29\"+\"%28x%2A2%28x-7%29%29%2F2\"=\"%285%2A2%28x-7%29%29%2F%28x-7%29\"\r
\n" ); document.write( "\n" ); document.write( "Since we can cancel out the same terms from both the numerator and denominator of each fraction, we are left with:\r
\n" ); document.write( "\n" ); document.write( "\"2%282x-9%29%2Bx%28x-7%29=2%2A5\"=\r
\n" ); document.write( "\n" ); document.write( "\"4x-18%2Bx%5E2-7x=10\"=\r
\n" ); document.write( "\n" ); document.write( "\"x%5E2-3x-18=10\"\r
\n" ); document.write( "\n" ); document.write( "If we subtract the 10 on the right side of the equal sign, from both sides, we are left with a quadratic equation:\r
\n" ); document.write( "\n" ); document.write( "\"x%5E2-3x-28=0\"\r
\n" ); document.write( "\n" ); document.write( "Let's see if we can solve this equation by factoring. We need to find out if any numbers that will multiply together and produce -28, can be added together to equal -3: 4 x -7= 28 and when we add 4 to -7, we get -3. So, turning this equation into factors, we get (x - 7)(x + 4) = 0, which means x = 7 and/or x = -4. Since we are unsure if either or both will work, we will have to substitute 7 and -4 for x in our original equation. Uh oh. Look at the first fraction in our equation. The denominator is x - 7. If we plug our 7 in for x, our denominator will equal 0. Denominators cannot equal 0, therefore, we know right away that 7 cannot be one of our solutions.\r
\n" ); document.write( "\n" ); document.write( "Now, let's try -4:\r
\n" ); document.write( "\n" ); document.write( "\"%282%28-4%29-9%29%2F%28-4-7%29%2B%28-4%2F2%29=5%2F%28-4-7%29\"=\r
\n" ); document.write( "\n" ); document.write( "\"%28-17%2F-11%29-2=5%2F%28-11%29\"=\r
\n" ); document.write( "\n" ); document.write( "\"%2817%2F11%29-2=-%285%2F11%29\"\r
\n" ); document.write( "\n" ); document.write( "The LCD of our remaining fractions is 11, so we would multiply 11 by each of our fractions by 11, which would leave us with the following:\r
\n" ); document.write( "\n" ); document.write( "\"17+-+22+=+-5\" =\r
\n" ); document.write( "\n" ); document.write( "\"-5+=+-5\"\r
\n" ); document.write( "\n" ); document.write( "since both sides of the equal sign are the same, we know that -4 is a solution.\r
\n" ); document.write( "\n" ); document.write( "Final Answer: x = -4
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