Here is another way. Rather than have your number as XY, write it as
10x + y.
Then using the second piece of info
10x+y - (10y+x) = 45
9x-9y=45
x-y=5
Since 10x + y is divisible by 8, it is an even number (\therefore y = 2, 4), and must be a multiple of 8.
Since 94 \nmid 8 \therefore...