document.write( "Question 242805: One number is eleven more than twice another. If their sum is decreased by nine, the result is seventeen. Find the numbers \n" ); document.write( "
Algebra.Com's Answer #177776 by oberobic(2304)![]() ![]() ![]() You can put this solution on YOUR website! In the setup to the problem, always try to minimize the unknowns. \n" ); document.write( "x = one number \n" ); document.write( "It is 11 more than twice another number. \n" ); document.write( "y = another number \n" ); document.write( "x = 2y + 11 \n" ); document.write( "... \n" ); document.write( "Now the second part says if the sum of x + y is decreased by 9 (that is: x + y - 9), the result is 17. \n" ); document.write( "x + y - 9 = 17 \n" ); document.write( "Add 9 to both sides \n" ); document.write( "x + y = 17+9 = 26 \n" ); document.write( "... \n" ); document.write( "Now we have to solve x and y \n" ); document.write( "... \n" ); document.write( "Subtracting y from both sides of the equation above. \n" ); document.write( "x + y - y = 26 - y \n" ); document.write( "x = 26 - y \n" ); document.write( "... \n" ); document.write( "Substituting in the other equation. \n" ); document.write( "x = 2y + 11 \n" ); document.write( "26 - y = 2y + 11 \n" ); document.write( "Adding y to both sides \n" ); document.write( "26 = 3y + 11 \n" ); document.write( "Subtracting 11 from both sides \n" ); document.write( "15 = 3y \n" ); document.write( "Dividing both sides by 3 \n" ); document.write( "5 = y \n" ); document.write( "... \n" ); document.write( "y = 5 \n" ); document.write( "... \n" ); document.write( "Recall \n" ); document.write( "x + y = 26 \n" ); document.write( "Substituting for y \n" ); document.write( "x + 5 = 26 \n" ); document.write( "Subtracting 5 from both sides \n" ); document.write( "x = 21 \n" ); document.write( "Check your work (even if you're tired)... \n" ); document.write( "Does x = 2y + 11? \n" ); document.write( "21 = 2(5) + 11? \n" ); document.write( "Yes it does. \n" ); document.write( "Does x + y - 9 = 17? \n" ); document.write( "21 + 5 - 9 = 17? \n" ); document.write( "Yes it does. \n" ); document.write( "So we're done. \n" ); document.write( "x = 21 \n" ); document.write( "y = 5 \n" ); document.write( " |