document.write( "Question 890826: Hey can you solve this please?: log4/9[(2x+1)/(x+3)]=-1/2 \n" ); document.write( "
Algebra.Com's Answer #539309 by Theo(13342)![]() ![]() You can put this solution on YOUR website! if i understand this correctly, the problem is:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log4/9(2x+1)/(x+3)=-1/2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "this is true if and only if (4/9)^(-1/2) = (2x+1)/(x+3)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(4/9)^(-1/2) = 1/(4/9)^(1/2) = 1/(2/3) = 3/2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "equation becomes:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3/2 = (2x+1)/(x+3)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "multiply both sides of the equation by 2 and multiply both sides of the equation by (x+3) to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3(x+3) = 2(2x+1)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "simplify to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3x+9 = 4x+2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "subtract 3x from both sides of the equation and subtract 2 from both sides of the equation to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "7 = x\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "that's your solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x = 7\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "when x = 7, your equation of log4/9[(2x+1)/(x+3)]=-1/2 becomes:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log4/9((2*7+1)/(7+3)) = -1/2 which becomes:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log4/9((15/10)) = -1/2 which becomes:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log4/9((3/2) = -1/2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you can solve this by translating it into an exponential equation.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you will get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log4/9((3/2) = -1/2 if and only if (4/9)^(-1/2) = 3/2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(4/9)^(-1/2) is equal to 1 / (4/9)^(1/2.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "1/(4/9)^(1/2) = 3/2 which becomes:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "1/(2/3) = 3/2 which becomes:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "3/2 = 3/2, confirming that x = 7 is the solution.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you could also have solved it by using the log base conversion formula and then using your calculator to get the log.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "start with:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log4/9((3/2) = -1/2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log conversion formula says that log4/9(3/2) = LOG(3/2)/LOG(4/9)\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "LOG is equal to log10 which is the same as log to the base of 10 which is what your calculator can handle.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your equation becomes:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "LOG(3/2)/LOG(4/9) = -1/2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "use your calculator to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "LOG(3/2)/LOG(4/9) = -.5.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "-.5 is the same as -1/2 so you're good and the solution is x = 7.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |