i need 75 eggs for a recipe how much liquid egg would that be?

The liquid egg package you are using will tell you how many eggs it is equivalent to, just read the package label.

A simple google search came up with this:

NOTE:
It has been brought to my attention that several don't use "liquid eggs" and would like to know how to convert to regular eggs.

Maybe this will help...
The net weight in ounces per dozen is the standard that is used to classify egg sizes.

* 1 dozen medium eggs = 21 ounces
* 1 dozen large eggs = 24 ounces
* 1 dozen extra large eggs = 27 ounces

Many recipes requiring eggs specify the use of large eggs, so if the eggs you have available are smaller or larger, it is beneficial to know the size equivalents. Use the following guidelines to achieve a quantity that should work well for most recipes.

* 5 medium eggs = 4 large eggs = 4 extra large eggs
* 6 medium eggs = 5 large eggs = 4 extra large eggs
* 7 medium eggs = 6 large eggs = 5 extra large eggs

For a more precise measure:
* 1 medium egg = 3 tablespoons
* 1 large egg = 3¼ tablespoons

Therefore:
* 13 medium eggs yields exactly the same quantity (39 tablespoons) as 12 large eggs.

What size egg does the recipe ask for? And where are you?
Most common size in American baking recipes is large (2 oz), of which 75 makes 18 3/4 liquid cup.
For size by weight and country around the world see:
https://en.wikipedia.org/wiki/Chicken_egg_sizes