document.write( "Question 1134465: pls help me with this, log27 base x + log4 base y = 5 ; log27 base x - log4 base y = 1. find x and y \n" ); document.write( "
Algebra.Com's Answer #751854 by Theo(13342)![]() ![]() You can put this solution on YOUR website! looks like you are solving two equations simultaneouosly with the twist that they involve logs.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the two equations are:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log27(x) + log4(y) = 5 \n" ); document.write( "log27(x) - log4(y) = 1\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "subtract the second equation from the first to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "2 * log4(y) = 4\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "divide both sides of this equation by 2 to get log4(y) = 2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "since log4(y) = 2, then both equations become:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log27(x) + 2 = 5 \n" ); document.write( "log27(x) - 2 = 1\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "add these two equations together to get:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "2 * log27(x) = 6\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "divide this equaion by 2 to get log27(x) = 3.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your solution so far is:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log27(x) + log4(y) = 5 which becomes 3 + 2 = 5 \n" ); document.write( "log27(x) - log4(y) = 1 which becomes 3 - 2 = 1\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "the equations have been solved simultaneously and what is left is to find the value of x and y.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "it was already determined that log27(x) = 3 and log4(y) = 2.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log27(x) = 3 if and only if 27^3 = x. \n" ); document.write( "this makes x = 19683.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log4(y) = 2 if and only if 4^2 = y. \n" ); document.write( "this makes y = 16.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "your solution is that x = 19683 and y = 16.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "you can confirm by using the base log conversion formula and your calculator.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log27(19683) = log(19683) / log(27) = 3\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "log4(16) = log(16) / log(4) = 2\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "solution is confirmed to be good.\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |