SOLUTION: PLEASE HELP...IF YOU DOUBLE A NUMBER AND THEN ADD 12, YOU GET ONE HALF OF THE ORIGINAL NUMBER. WHAT IS THE ORIGINAL NUMBER?

Question 494026: PLEASE HELP...IF YOU DOUBLE A NUMBER AND THEN ADD 12, YOU GET ONE HALF OF THE ORIGINAL NUMBER. WHAT IS THE ORIGINAL NUMBER?
Answer by bucky(2189) (Show Source): You can put this solution on YOUR website!
Let x be the original unknown number.
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Double that number means taking 2 times x which is written as 2x.
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Then add 12 to that and you have 2x + 12
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The problem tells you that this should equal 1/2 of the original number, or (1/2)x
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Setting these two quantities equal results in the equation:
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2x + 12 = (1/2)x
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You can get rid of the fraction on the right side by doubling both sides of this equation ... Do that by multiplying both sides (all terms) by 2 and the equation becomes:
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4x + 24 = x
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Subtract x from both sides:
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3x + 24 = 0
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Then subtract 24 from both sides:
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3x = -24
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Finally solve for x (the original number) by dividing both sides of this equation by 3 to get:
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x = -24/3 = -8
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So the answer is that the original unknown number is -8.
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Check it out. Double it to get -16 then add 12 to the -16 and the result is -4. This checks because it is supposed to equal half the original number which is one-half of -8. And it does.
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This checks the answer. The original number is -8.
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Hope this helps you to understand the problem.
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