Let us consider a positive charge placed at a distance x$x$ on left outside the cube of side a$a$. The electric fields are entering the cube from left and exiting from the right. Will the flux in the cube be zero or will it have a finite value?
The electric field varies inversely with distance as E$E$ proportional to 1/r^2$1/r^2$. Since Areaarea is same, would the flux through the left side be greater than flux through right?
E.A=A.kq/x^2$$E.A=A.kq/x^2$$ E'.A=A.kq/(x+a)^2$$E'.A=A.kq/(x+a)^2$$