The gallbladder is a small pouch that sits just under the liver. The gallbladder stores bile produced by the liver. After meals, the gallbladder is empty and flat, like a deflated balloon.efore a meal, the gallbladder may be full of bile and about the size of a small pear. In response to signals, the gallbladder squeezes stored bile into the small intestine through a series of tubes called ducts. Bile helps digest fats, but the gallbladder itself is not essential.
U-substitution is for functions that can be written as the product of another function and its derivative. $$\int u du$$. Integration by parts is for functions that can be written as the product of another function and a third function's derivative.
Substitution, used usually when one of the variables are already solved for. The other two methods are Elimination, and solving it graphically. substitution, linear multiplication, graphing. have fun. then you have one simple answer and can plug it in easily.