SOLUTION: .a two-digit number is three less than seven times the sum of two digits.if the digits are reserved,the new numberis 18 less than the original number.whats the original number?

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Question 530299: .a two-digit number is three less than seven times the sum of two digits.if the digits are reserved,the new numberis 18 less than the original number.whats the original number?
Answer by stanbon(75887) About Me  (Show Source):
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a two-digit number is three less than seven times the sum of two digits.if the digits are reserved,the new numberis 18 less than the original number.whats the original number?
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Let the number be 10t+u
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Equations:
10t+u = 7(t+u)-3
10u+t = 10t+u-18
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Rearrange:
3t - 6u = -3
9t - 9u = 18
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Modify:
9t - 18u = -9
9t - 9u = 18
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Subtract and solve for "u":
9u = 27
u = 3
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Solve for "t":
3t-6u = -3
t -2u = -1
t -2*3 = -1
t = 5
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Ans: Original Number: 53
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Cheers,
Stan H.
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