Numerical values for the first "x" would include the integers 1-9. The "grunt" method here would be to divide 13579x by 42, then 23579x by 42, and so on, to determine whether or not a value of x can be found that results in NO remainder. Let's assume that "x" has the same value at the end of each "x3479x as it does in the beginning:
135791
235792
335793
and so on.
Note immediately that x must be an even digit, since no multiple of 42 results in an odd final digit to x3479x.
Thus, from x=1 through 9, we eliminate 1, 3, 5, 7, 9 and investigate x = 2, 4, 6, 8.
Does 42 divide into 235792 without a remainder? No.
Does 42 divide into 435794 without a remainder? No.
Does 42 divide into 635796 without a remainder? Yes. The quotient is 15138.
So: the desired number is 635796, and 42 / 635796 = 15138.
