Answer
$$ -8 \pi $$
Work Step by Step
As we know that $ div F=\dfrac{\partial A}{\partial x}i+\dfrac{\partial B}{\partial y}j+\dfrac{\partial C}{\partial z}k $
From the given equation, we have
$$ Flux =\iiint_{o}(x-1) dz dy dx \\ =\nabla \cdot F=\int_{0}^{2\pi}\int_{0}^{2}\int_{0}^{r^2} (r \cos \theta-1) \space dz \space dr \space d\theta\\=\int_{0}^{2 \pi}(\dfrac{32}{5}\times \cos \theta -4) d\theta \\= -8 \pi $$
