SOLUTION: Word Problems : three times one nuber added to another is eighteen. Twice the first number minus the other number is twelve. Fid the numbers. I really need to learn how to set th

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Question 424231: Word Problems :
three times one nuber added to another is eighteen. Twice the first number minus the other number is twelve. Fid the numbers. I really need to learn how to set this up! Its very confusing. Thanks!
Answer by MichelleL(6) About Me  (Show Source):
You can put this solution on YOUR website!
Let's write the first equation:
“three times one nuber added to another is eighteen” can be represented by this equation: 3x+y=18 where x is one number and y is another.
Now lets write the other equation:
“Twice the first number minus the other number is twelve”. This can be written by: 2x-y=12.
We now have two equation:
3x+y=18 and 2x-y=12 and two unknowns: x and y.
Lets solve first for x. Sum both equation:
3x+y+2x-y=18+12
5x=30
x is then 6.
Lets take the second equation (2x-y=12) , replace x by 6 then find y:
2*6-y=12 or 2*6-12=y. y is then 0.