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?

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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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