document.write( "Question 1199298: A first number plus twice a second number is 13. Twice the first number plus the second totals 32. Find the numbers \n" ); document.write( "
Algebra.Com's Answer #833117 by greenestamps(13200)\"\" \"About 
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\n" ); document.write( "You have received two good responses showing typical algebraic solutions. For this particular problem, because of the form of the given information, there is a different path to the solution that conceptually is much easier, although the formal algebra for this path is not more efficient.

\n" ); document.write( "A first number plus twice a second number is 13. Twice the first number plus the second totals 32.

\n" ); document.write( "Informally, using only mental arithmetic and logical reasoning, we can solve the problem like this:

\n" ); document.write( "(1) Add the two pieces of given information to find that 3 times the first number plus 3 times the second number is 45.
\n" ); document.write( "(2) From that, conclude that the sum of the two numbers is 15.
\n" ); document.write( "(3) Compare (2) to the fact that the first number plus twice the second number is 13 to conclude that the second number is -2.
\n" ); document.write( "(4) Use (2) and (3) to conclude that the first number is 17.

\n" ); document.write( "ANSWERS: 17 and -2

\n" ); document.write( "While that method of solving the problem informally is fast and easy, using formal algebra for that path to the solution is not very efficient....

\n" ); document.write( "(1) \"x%2B2y=13\"
\n" ); document.write( "(2) \"2x%2By=32\"
\n" ); document.write( "(3) \"3x%2B3y=45\" [add (1) and (2)]
\n" ); document.write( "(4) \"x%2By=15\" [divide by 3]
\n" ); document.write( "(5) \"y=-2\" [subtract (4) from (1)]
\n" ); document.write( "(6) \"x=17\" [from (4) and (5)]

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