Firstly we will look
1) What Supply is?
2) What Demand is?
3) What is the Supply Law?
4) What is the Demand Law?

Supply is the amount of certain product which producer is able to sell at a given price.
Demand is the desire of consumer, his willingness and ability to pay for a certain good or service

The supply law shows the quantaties that will be sold at a certain price. It states that the higher the Quantaty supplied, the higher the price.
The law of demand states that, if all other factors remain equal, the higher the price of a good, the less people will demand that good. In other words, the higher the price, the lower the quantity demanded.

Actually, this laws are used by marketings to predict the demand of people and come to the equillibrium 

Снизу представлена моя работа о спросе и предложении.