Not too sure how to approach this equation - fluids mechanics

Apologies if anything has been left out.

Ok, so there is just 1 equation which I am struggling to understand, I have made an attempt and also written out the full equation in 2 parts, but I dont know whether I need to use just the 1st half of the equation to get the dynamic viscosity or use both halves of the equation and if I need to use both halves, I am unsure how to.

My main course is the electrical and electronic side, so we dont usually see much or so far I havent seen much of the combining side where youd usually use P1 and P2. If its just using the first part of the equation then its something id be able to do.

My last question is about the coefficient of viscosity, how exactly would I obtain this value? I understand the basic knowledge that in my position, Syrup is high viscosity while water is low viscosity. So the higher the density the higher the viscosity, but how do I get the actual coefficient value? Id assume its not a simple google search of, coefficient of viscosity of water, as it comes up with the dynamic visc, which is something I need to work out for the table or is it that simple? I was given no information on how to work the value out.

Any guidance would be appreciated.