Question 911608
Let {{{ u }}} = the units digit
Let {{{ t }}} = the tens digit
The "value" of the number is:
{{{ 10t + u }}}
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(1) {{{ u = 8*t }}}
Right away you know that {{{ t = 1 }}}
Anything higher would make {{{ u }}}
a 2-digit number
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(2) {{{ 10t + u - ( 10u + t ) = -63 }}}
Since {{{ t=1 }}},
(2) {{{ 10 + u - 10u - 1 = -63 }}}
(2) {{{ -9u = -63 - 9 }}}
(2) {{{ -9u = -72 }}}
(2) {{{ u = 8 }}}
The number is 18