document.write( "Question 845209: A number is 6 greater than 1/2 another number. The sum is 21, find the 2 numbers. \n" ); document.write( "
Algebra.Com's Answer #509176 by pmesler(52)![]() ![]() You can put this solution on YOUR website! Let x = some number\r \n" ); document.write( "\n" ); document.write( "Let y = the second number.\r \n" ); document.write( "\n" ); document.write( "Therefore x = (y/2 + 6).\r \n" ); document.write( "\n" ); document.write( "The problem says that x+y = 21.\r \n" ); document.write( "\n" ); document.write( "All we have to do is substitute what we know x is into the equation and solve for y.\r \n" ); document.write( "\n" ); document.write( "Therefore x+y = 21 becomes\r \n" ); document.write( "\n" ); document.write( "(y/2 + 6) + y = 21\r \n" ); document.write( "\n" ); document.write( "Now we need to isolate the y on the left side, but before we do that we need to combine like terms. We can't combine the y terms until both y's share the same denominator. To do this we need to multiply the second y by 2/2. That will give us the following:\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(y/2 + 6) + y(2/2) = 21\r \n" ); document.write( "\n" ); document.write( "We can multiply by 2/2 because 2/2 = 1 and multiplying anything by 1 does not change the value of the number. All we're doing is changing the form, not the value of the expression. \r \n" ); document.write( "\n" ); document.write( "Our new equation is this:\r \n" ); document.write( "\n" ); document.write( "(y/2 + 6) + (2y/2) = 21\r \n" ); document.write( "\n" ); document.write( "Now we can combine the y terms and we get\r \n" ); document.write( "\n" ); document.write( "3y/2 + 6 = 21.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Subtract 6 from both sides to simplify.\r \n" ); document.write( "\n" ); document.write( "3y/2 = 15\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "Now to get y by itself we need to multitply both sides by the reciprocal of 3/2 which is 2/3. We do this so the numerator and denominators divide out and all we are left with is y.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "(2/3)(3y/2) = 15(2/3).\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "y = 15 * 2/3\r \n" ); document.write( "\n" ); document.write( "y = 30/3\r \n" ); document.write( "\n" ); document.write( "y = 10. Now that we know that y = 10, it will be simple to find x.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "x as you remember is (y/2 + 6)\r \n" ); document.write( "\n" ); document.write( "Therefore x = (10/2 + 6)\r \n" ); document.write( "\n" ); document.write( "x = 5 + 6\r \n" ); document.write( "\n" ); document.write( "x = 11. \r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( "This checks out since 11 + 10 = 21. \n" ); document.write( " |