document.write( "Question 76649: I need to solve for x. I believe the answer if 4 but I have no idea how to start.
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document.write( "(2x-3/x-1)-(x-1/x+2)=(2x-5/x+2)+(2-x/1-x) \n" );
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Algebra.Com's Answer #54971 by bucky(2189)![]() ![]() ![]() You can put this solution on YOUR website! Sort of a long problem. Given: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Notice that the denominators are (x - 1), (x + 2), and (1 - x). Sure would be nice if \n" ); document.write( "that denominator (1 - x) was (x - 1) so it was like the other one. So let's apply a little \n" ); document.write( "math trick to the last term on the right side. Let's multiply the numerator and the denominator \n" ); document.write( "inside the parentheses by \n" ); document.write( "are equal, it is the same as multiplying the fraction inside the parentheses by 1, so it does \n" ); document.write( "not change anything ... except it reverses the signs of the terms in the parentheses. \n" ); document.write( "When you do that manipulation, the last term on the right side becomes: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "and the equation becomes: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Now we're ready to rumble! Let's multiply every term on both sides by the product of \n" ); document.write( "the common terms in the denominator. In other words, let's multiply everything by the \n" ); document.write( "product (x-1)*(x+2). When we do, the problem becomes: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Now we can cancel any terms in the denominator that have the same term in the numerator as \n" ); document.write( "shown: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "And the problem is reduced to: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "This is now just an \"ordinary\" algebraic equation. Let's multiply out the all the terms to \n" ); document.write( "get: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Remove the parentheses. If they are preceded by a + sign, just erase them. If they are \n" ); document.write( "preceded by a minus sign, when you remove them, change the sign of all the terms inside. When \n" ); document.write( "you remove the parentheses you get: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Grouping like terms on the left and right side results in: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Combining like terms gives you: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Since this is going to be a quadratic equation, let's get it into standard form by moving \n" ); document.write( "everything to the left side and just have a zero on the right side. Do this by subtracting \n" ); document.write( " \n" ); document.write( "subtraction results in: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Combine like terms to get: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Simplify by dividing both sides by -2: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "This quadratic factors to: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "and this equation will be true if either factor on the left side is zero. So one at a \n" ); document.write( "time set the factors equal to zero and solve for x. \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Next: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "But this last solution has to be ignored. Why??? Go way back to the original problem and \n" ); document.write( "note what happens if x = 1. If it does = 1 then a couple of the denominators become \n" ); document.write( "zero, and division by zero is not allowed. Therefore, x = 1 is not a valid answer. The \n" ); document.write( "only acceptable answer is x = 4. \n" ); document.write( ". \n" ); document.write( "You can check that by returning to the original problem and substituting 4 for x to see if \n" ); document.write( "the left side of the equation still equals the right side. You should find that it does. \n" ); document.write( ". \n" ); document.write( "Hope this helps you to see your way through the problem. \n" ); document.write( " \n" ); document.write( " |