Economists use the term “comparative statics” to refer to changes in equilibrium. I talked before about how the forces of supply and demand come together to determine prices and quantities in a market, and now we can look at what happens to those equilibrium prices and quantities when there is a shock to supply, demand, or both. (Hint: Price increases are quite often the result of market forces and not simply due to the fact that corporations are evil. Just saying.)
The next two videos go through the algebra of shifting these curves around and determining the quantitative changes in equilibrium price and quantity. These are here mainly for those who are in an economics class and are going to need to do this at some point. For a general audience, the videos above are totally sufficient.