document.write( "Question 572140: 14/(x+4)=5-x \n" ); document.write( "
Algebra.Com's Answer #368664 by mathsmiles(68)![]() ![]() You can put this solution on YOUR website! 14/(x+4)=5-x\r \n" ); document.write( "\n" ); document.write( "The first thing I'd do is get rid of the (x+4) so we don't have a fraction anymore \n" ); document.write( "Do that by multiplying both sides by (x+4) giving ... \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "14 = (5-x)(x+4) Now multiply out the parens using FOIL ... \n" ); document.write( "14 = 5x + 20 - x^2 - 4x Rearranging the terms ... \n" ); document.write( "14 = -x^2 + 5x - 4x + 20 Now combine the x terms ... \n" ); document.write( "14 = -x^2 + x + 20 Now let's get all the factors on one side of the equation so we can solve. Subtract 14 from both sides ... \n" ); document.write( "-x^2 + x + 6 = 0 I like to make the x^2 term positive, so let's multiply by (-1) \n" ); document.write( "(-1)(-x^2 + x + 6) = 0 \n" ); document.write( "x^2 - x - 6 = 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now we need to factor into two multipliers: \n" ); document.write( "(x _ _)(x _ _) = 0 where each _ represents something we need to figure out, both the operator and the term\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Since the last term is negative, we know we need one of each + and - operators: \n" ); document.write( "(x - _)(x + _) = 0\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now we need factors of 6 which are different by 1 to get the -x terms: \n" ); document.write( "Factors of 6: \n" ); document.write( "6 = 2 * 3 That'll do it!\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Since we want the middle x term to be negative, let's place 3 in the negative paren giving: \n" ); document.write( "(x - 3)(x + 2) = 0 \n" ); document.write( "Now we have two possibilities for x: \n" ); document.write( "x-3 = 0 Adding 3 to each side: \n" ); document.write( "x = 3 \n" ); document.write( "OR \n" ); document.write( "x+2 = 0 Adding -2 to each side: \n" ); document.write( "x = -2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Since your problem didn't specify positive or negative, either of these should work. Let's check: \n" ); document.write( "14/(x+4)=5-x Substituting x=3 \n" ); document.write( "14/(3+4)= 5-3 \n" ); document.write( "14/7 = 5-3 \n" ); document.write( "2 = 2 Correct!\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "14/(x+4) = 5-x Substituting x=-2: \n" ); document.write( "14/(-2+4) = 5-(-2) Converting the double negative on the right to positive: \n" ); document.write( "14/(2)=5+2 \n" ); document.write( "14/2 = 7 \n" ); document.write( "7=7 Correct!\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |