help number theory

First we know that x ≠ odd. This is because for it to be divisible by 42, it needs to be even. 

 

This means we can try 2, 4, 6 and 8 as x

 

235792 ÷ 42 ≈ 5614.0952

 

435794 ÷ 42 ≈ 10,376.0476

 

635796 ÷ 42 = 15,138

 

835798 ÷ 42 ≈ 19,899.9524

 

This means x = 6, which is your answer :)

Has to end in an even number

 

trial and error shows   x = 6