Gauss's law: calculating enclosed charge

A cuboidal surface of dimensions $4.0\text{m}\times 2.0\text{m}\times 2.0\text{m}$‍ is located near the origin of a coordinate system, as shown below.

Two its faces normally intersect the $x$‍-axis at $x=1.0\text{m}$‍ and $x=5.0\text{m}$‍ respectively.

A non-uniform electric field, $\mathbf{E}=({\displaystyle \frac{10}{x}})\hat{\mathbf{i}}{\displaystyle \frac{\text{N}}{\text{m}}}$‍, is present in the region.

$Q_{\text{net}}=($‍ $\times {ϵ}_0)\text{C}$‍