Question 248822: twice one number added to another number is 18. four times the first number minus the other number is 12. find the numbers. Answer by oberobic(2304) (Show Source):
You can put this solution on YOUR website! The statements become the following equations.
2x + y = 18
4x - y = 12
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2x + y = 18
Subtract 2x from both sides
y = -2x + 18
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Substitute into the 2nd equation
4x - (-2x + 18) = 12
4x +2x - 18 = 12
Combine terms
6x -18 = 12
Add 18 to both sides
6x = 30
Divide both sides by 6
x = 5
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Looking back, we recall:
2x + y = 18
4x - y = 12
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2(5) + y = 18
10 + y = 18
Subtract 10 from both sides
y = 8
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4(5)-8 = 12
True
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So the two numbers are:
x = 5
y = 8
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