Answer:
A Linear Function is any function that graphs to any straight line. It can be consist of one or 2 or more variables but the degree or the exponent value of the variable shouldn't be greater than 1. it can be 0 but not greater than one .
Explanation:
f(x)= y= a +bx , is the example of linear fucntion where the variable x has the exponent value of 1 ,
but the function f(x)= y= a+bx^2 is not a linear function because the exponent value of variable x is 2 .
Also if the Value of Exponent of the variable is in negative, that will be also a non linear function .