Question

XYZ=?
XYZ (cu bara sus)-ZYX(cu bara sus ) =99

Answer 1

xyz-zyx=99
100x+10y+z-100z-10y-x=99
99x-99z=99
99(x-z)=99
x-z=1 => x = { 2, 3 ,4 ,5 ,6 ,7 ,8 ,9 } si z = { 1, 2 ,3 ,4 ,5 ,6 ,7 ,8  }
x=2=>z=1=>y={1,2,3......9} => xyz=211, 212,213............219
x=3=>z=2=>y={1,2,3....9}=> xyz= 321,322..........329
...
.
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x=9=>z=8=> y = { 1,2 ........ 9 }=> xyz=981,982..........989
In total 72 de solutii.