Answer:
There is no certain answer because answer is in words. In mathematical terms
consider f(x) =x + 2, f(x)= x² + 3x +2,
You have to write polynomials having single variable having any degree will be a function.
Step-by-step explanation:
Real life example :
There are thousands of examples and i am writing few of them.
1. From a set of parents each having a single child either son or daughter is a function . which is represented as a function , each having a unique outcome
2. There are different kind of employees in an office or in a system ,or in a country working in government or private sector ranging in Different Grades. Each employee get salary according to rank they possess or the qualification they have.
3. Consider Food you eat and specific nutrients they possess. So, [ Type of Food⇒Nutrients contained in them] are functions.
This type of equation is useful because for each of these examples we can make different equations .Let me make one for you.
Suppose you eat Egg. Represent it by y.it has 4 nutrients (a)Protein (b) Riboflavin (c) Selenium (d) Vitamin.
So if i will write it in terms of equation we can write
y =x²+x+2 [ Considering x=1,we get number of nutrients possessed by egg]
So,by this way we can say these equations are useful.