Willl givee a

solve: 4^3x = 42

Ok, ok, 

4 x 4 x 4 = 64
64 x (x) = 42
64 x 2/3 = 42.6666667

This seems like a crazy answer and it's probably wrong but i think it's 0.89871957046 because when you times that by 3 you get 2.69615871139 and 4 to the power of 2.69615871139 is 42.. 

Why are u not just putting the numbers this is to much

Your maths is very weak try yourself this would improve your skills don't depend on others