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unknown wrote at 2009-12-14 19:08:17
let t represent the tens'digit, let u represent the units'digit

t=u+3

1ot+u=6(t+u)+8

we substute t by u+3 in eq.2

10(u+3)+u=6(u+3+u)+8

10u+30+u=6u+18+6u+8

11u+30=12u+26

4=u



we replace u by 4 in eq.1

t=4+3

t=7



the number is 74



to check replace the digits in the equation :)


Ian wrote at 2011-07-27 06:28:03
let t be your tens digit

u be the units digit



tens digit is 3 more than the units digit.

(t=3+u)



The number (whole number) is 8 more than six times the sum of the digits.

[10t+u=6(t+u)+8] ----> distribute 6 to the sum of the digits (t+u)



[10t+u=6t+6u+8]



substitute t with 3+u



10(3+u)+u=6(3+u)+6u+8 {distribute the numbers six and ten}



30+10u+u=18+6u+6u+8 (combine similar terms)



30+11u=26+12u



add (-30 and -12u to both sides)



30+(-30)+(-12u)+11u=26+(-30)+12u+(-12u)



-u=-4



then multiply both sides with -1



-1(-u)=-1(-4)



u=4



t=3+u then t=3+4



t=7 and u=4



The number is 74. :)







-Ian


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