document.write( "Question 1131188: The sum of three numbers is 15. The sum of twice the first​ number, 4 times the second​ number, and 5 times the third number is 49. The difference between 3 times the first number and the second number is 16. Find the three numbers. \n" ); document.write( "
Algebra.Com's Answer #747815 by ankor@dixie-net.com(22740)\"\" \"About 
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The sum of three numbers is 15.
\n" ); document.write( "a + b + c = 15
\n" ); document.write( " The sum of twice the first​ number, 4 times the second​ number, and 5 times the third number is 49.
\n" ); document.write( "2a + 4b + 5c = 49
\n" ); document.write( " The difference between 3 times the first number and the second number is 16.
\n" ); document.write( "3a - b = 16
\n" ); document.write( ":
\n" ); document.write( " Find the three numbers.
\n" ); document.write( ":
\n" ); document.write( "Add the 1st and the 3rd equations
\n" ); document.write( "a + b + c = 15
\n" ); document.write( "3a -b + 0 = 16
\n" ); document.write( "-----------------adding eliminates b
\n" ); document.write( "4a + 0 + c = 31
\n" ); document.write( "4a + c = 31
\n" ); document.write( ":
\n" ); document.write( "multiply the 1st equation by 4 and subtract the 2nd equation
\n" ); document.write( "4a + 4b + 4c = 60
\n" ); document.write( "2a + 4b + 5c = 49
\n" ); document.write( "-------------------subtraction eliminates b
\n" ); document.write( "2a + 0 - c = 11
\n" ); document.write( "2a - c = 11
\n" ); document.write( ":
\n" ); document.write( "Add the two resulting equations
\n" ); document.write( "4a + c = 31
\n" ); document.write( "2a - c = 11
\n" ); document.write( "----------------adding eliminates c, find a
\n" ); document.write( "6a + 0 = 42
\n" ); document.write( "a = 42/6
\n" ); document.write( "a = 7
\n" ); document.write( ":
\n" ); document.write( "use the 3rd equation to find b
\n" ); document.write( "3a - b = 16
\n" ); document.write( "3(7) - b = 16
\n" ); document.write( "-b = 16 - 21
\n" ); document.write( "-b = -5
\n" ); document.write( "b = 5
\n" ); document.write( ":
\n" ); document.write( "Find c using the 1st equation
\n" ); document.write( "7 + 5 + c = 15
\n" ); document.write( "c = 15 - 12
\n" ); document.write( "c = 3
\n" ); document.write( ":
\n" ); document.write( ":
\n" ); document.write( "Chck solutions in the 2nd equation
\n" ); document.write( "2(7) + 4(5) + 5(3) =
\n" ); document.write( "14 + 20 + 15 = 49
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