document.write( "Question 201758: perform indicated operation, simplifying if possible.
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document.write( "x^2+3x-4/x^2-x-20 * 5x-25/5x^2-x please show step by step. also what is the difference between X^2+3x-4 and X^2-3x-4 how do you factor them I came up with (x+1)(x-4) \n" );
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Algebra.Com's Answer #152018 by PRMath(133)![]() ![]() ![]() You can put this solution on YOUR website! perform indicated operation, simplifying if possible. \n" ); document.write( "x^2+3x-4/x^2-x-20 * 5x-25/5x^2-x please show step by step. also what is the difference between X^2+3x-4 and X^2-3x-4 how do you factor them I came up with (x+1)(x-4)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Ok, first think back to grade school math for a second, because these concepts connect, k? Remember that 4/4 equals 1, right? That's one concept to keep in your mind.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Another concept is that you can cancel out FACTORS (multiplication) in a fraction. For example: 4x/4 means that you can look at 4/4 and realize it equals 1 and then that just leaves the \"x\". \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now that you have those thoughts in your head, let's look at your problem.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "It is this:\r \n" ); document.write( "\n" ); document.write( "x^2+3x-4/x^2-x-20 * 5x-25/5x^2-x \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "So I would first factor everything I could factor. Let's start with:\r \n" ); document.write( "\n" ); document.write( "x^2+3x-4. You have to think, what can you use that will MULTIPLY to get \"-4\" yet at the same time, will ADD up to equal \"+3\".\r \n" ); document.write( "\n" ); document.write( "So, let's factor in this way: (x + 4)(x - 1) \r \n" ); document.write( "\n" ); document.write( "Remember FOIL? Check to see if we factored correctly.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Let's now factor: x^2-x-20 \r \n" ); document.write( "\n" ); document.write( "Sooooo what can you do that will MULTIPLY to get \"-20\" yet at the same time, will ADD up to be \"-1\"? \r \n" ); document.write( "\n" ); document.write( "We can factor the equation this way: (x - 5)(x + 4)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We are not done yet. Now we have to factor: 5x-25\r \n" ); document.write( "\n" ); document.write( "Do you see a number there that is common to both the \"5\" and the \"25\"???\r \n" ); document.write( "\n" ); document.write( "How about the number \"5\"?\r \n" ); document.write( "\n" ); document.write( "SOooo let's factor this way: 5(x - 5)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "We are STILL not done. Now we have to factor: 5x^2-x \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "What is common to the 5x^2 and the \"X\"????? How about \"x\"??\r \n" ); document.write( "\n" ); document.write( "So, let's factor this way: x(5x - 1)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Wow, we just did a lot of factoring. Now will will put that info all together to see what we can cancel out, k?\r \n" ); document.write( "\n" ); document.write( "Here we go:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(x + 4)(x - 1) 5(x - 5) \n" ); document.write( "________________________________ \n" ); document.write( "(x - 5)(x + 4) x(5x - 1)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "The above is the SAME problem you wrote, but everything has been factored out. Now we can do some canceling. I'm not sure how to show this to you. I really want to highlight the cancellations or do a strike over. Hmmmm. \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(x + 4)(x - 1) 5(x - 5) \n" ); document.write( "_________________________ \n" ); document.write( "(x - 5)(x + 4) x(5x - 1)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "I think the only thing I can do is tell you in this way:\r \n" ); document.write( "\n" ); document.write( "(x+4)in the numerator cancels out (x+4) in the denominator. \n" ); document.write( "(x-5) in the numerator cancels out (x-5) in the denominator.\r \n" ); document.write( "\n" ); document.write( "Now you are left with:\r \n" ); document.write( "\n" ); document.write( "(x - 1)5 \n" ); document.write( "_________ \n" ); document.write( "x(5x - 1)\r \n" ); document.write( "\n" ); document.write( "You cannot cancel out the \"X\" variables, because in the numerator (x - 1) is not factorable. \r \n" ); document.write( "\n" ); document.write( "So your answer is(assuming I understood what you wrote as the question) is:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "5(x - 1) \n" ); document.write( "_________ \n" ); document.write( "x(5x - 1)\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( "You also wanted to know: what is the difference between \n" ); document.write( "X^2+3x-4 and X^2-3x-4. How do you factor them? I came up with (x+1)(x-4)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Here's your first equation: X^2+3x-4\r \n" ); document.write( "\n" ); document.write( "Think of this: What can you MULTIPLY to get \"-4\" and yet ADD to get \"+3\"\r \n" ); document.write( "\n" ); document.write( "It would factor like this: (x +4)(x-1)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Here's your 2nd equation: X^2-3x-4\r \n" ); document.write( "\n" ); document.write( "Again, what can you MULTIPLY to get \"-4\" and yet ADD to get a \"-3\". (In the previous problem, you wanted a POSITIVE 3 but this time you want a NEGATIVE 3).\r \n" ); document.write( "\n" ); document.write( "This 2nd equation would factor like this: (x -4)(x +1)\r \n" ); document.write( "\n" ); document.write( "Good luck. Hope this helps. :-) \n" ); document.write( " |