# State an equation for conservation of mass and use it to show that fluids of constant density are incompressible

I have the following question:

State an equation for conservation of mass and use it to show that fluids of constant density are incompressible

My solution (1):

My solution (2):

I don't know how to use the 2nd equation for conservation of mass the get the solution.

Fluid of constant density means that $$\frac{\partial p}{\partial t} =0$$ but it doesn't mean $$\frac{Dp}{Dt} =0$$