SOLUTION: When the first of two numbers is added to twice the second the result is 21, but when the second number is added to twice the first the result is 18. Find the two numbers.

Question 151379: When the first of two numbers is added to twice the second the result is 21, but when the second number is added to twice the first the result is 18. Find the two numbers.
Answer by oscargut(2103) (Show Source): You can put this solution on YOUR website!
Let a the first number and b the second one
When the first of two numbers is added to twice the second the result is 21,
then a+2b=21
when the second number is added to twice the first the result is 18.
then 2a+b =18
a+2b=21
2a+b =18
doing first eq by -2 we have
-2a+-4b=-42
2a+b=18
adding both eq
-3b=-24
b=8 and a+2(8)=21
then a+16=21
a=5
Solution: a=5 and b=8

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