document.write( "Question 108092: in need of help with:solve algebraically ln 2+ ln(x-6)=ln(x+2) \n" ); document.write( "
Algebra.Com's Answer #78750 by bucky(2189) ![]() You can put this solution on YOUR website! Given: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "By the rules of logarithms, when you add to logarithms it is equivalent to the logarithm \n" ); document.write( "of their product. Therefore, the left side of the given equation can be changed as indicated \n" ); document.write( "below: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Look carefully at this equation. Both sides have the natural logarithm of a quantity. \n" ); document.write( "So for the equation to be true, the quantities on which the logarithm operates have to \n" ); document.write( "be equal. This being the case, then we can say: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "so that in the given equation the natural logarithm operator is acting on two equal quantities. \n" ); document.write( ". \n" ); document.write( "Now we can work on solving for x by solving the equation: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Multiplying out the left side changes this equation to: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Get rid of the 12 on the left side by adding 12 to both sides of this equation to get: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "Next get rid of the x on the right side by subtracting x from both sides to reduce the \n" ); document.write( "equation to: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "So the answer to this problem is x = 14. \n" ); document.write( ". \n" ); document.write( "You can check this answer by returning to the given problem. Substituting 14 for x in the \n" ); document.write( "given equation results in: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "This simplifies to: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "At this point you can use a calculator to look up each of these three natural logarithms. \n" ); document.write( ". \n" ); document.write( "ln(2) = 0.69314718 \n" ); document.write( "ln(8) = 2.079441542 \n" ); document.write( "ln(16) = 2.772588722 \n" ); document.write( ". \n" ); document.write( "Substituting these values for the natural logarithms of the equation results in: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "When you complete the addition on the left side you get: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \n" ); document.write( "This tells you that when x = 14 the equation is correct. \n" ); document.write( ".\r \n" ); document.write( "\n" ); document.write( "Hope this helps you to understand the problem and the process you can use to find the \n" ); document.write( "answer for the value of x. \n" ); document.write( ". \n" ); document.write( " |