While solving mathematical problems, you may have seen types of equations. Few Equations can contain only numbers, others consist of only variables while some consists of both numbers and variables.
Linear and nonlinear equations usually consist of numbers as well as variables.
Before starting with the difference between linear and nonlinear equations, let us first understand the definition of Linear and NonLinear Equation.
Linear Equation: A linear equation is such which forms a straight line. Linear means something related to a line. All the linear equations are used to construct a line. Linear Equations are conditions of the principal request. These conditions are characterized by lines in the arranged framework. An equation for a straight line is known as a Linear equation. The overall portrayal of the straightline condition is y=mx+b, where m is the slant of the line and b is the ycatch.
NonLinear Equations: A nonlinear equation is such which does not form a straight line. It looks like a curve in a graph and has a variable slope value. A nonlinear equation is generally given by ax^{2}+by^{2} = c
where x and y are variables
a,b and c are constant values.
The major difference between linear and nonlinear equations is given here for the students to understand it in a more natural way. The differences are provided in a tabular form with examples.
To find the difference between the two equations, i.e. linear and nonlinear, one should know the definitions for them. So, let us define and see the difference between them.
S No.  Linear Equations  NonLinear Equations 
1.  It forms a straight line or represents the equation for the straight line  It does not form a straight line but forms a curve. 
2.  It has only one degree. Or we can also define it as an equation having the maximum degree 1.  A nonlinear equation has the degree as 2 or more than 2, but not less than 2. 
3.  All these equations form a straight line in XY plane. These lines can be extended to any direction but in a straight form.  It forms a curve and if we increase the value of the degree, the curvature of the graph increases. 
4. 
The general representation of linear equation is; y = mx +c Where x and y are the variables, m is the slope of the line and c is a constant value. 
The general representation of nonlinear equations is; ax^{2} + by^{2} = c Where x and y are the variables and a, b and c are the constant values 
5.  Linear Equations are much simpler to solve.  Nonlinear Equations are tricky in nature. 
6.  Linear Equations are time saving.  Nonlinear equations are timeconsuming. 
7. 
Examples:

Examples:

Sample Problems on Linear and Nonlinear Equations
Problem 1: Solve the linear equation 3x+18 = 2x + 21.
Solution:
Given, 3x+18 = 2x + 21
⇒ 3x – 2x = 21 – 18
⇒ x = 3
Problem 2: Solve x = 12(x +2)
Solution:
x = 12(x + 2)
x = 12x + 24
Subtract 24 from each side
x – 24 = 12x + 24 – 24
x – 24 = 12x
Simplify
11x = 24
Isolate x, by dividing each side by 11
11x / 11 = 24/11
x = 24/11
Problem 3: Solve the nonlinear equation x+4y = 1 and x = y.
Solution:
Given, x+4y = 1
x = y
By putting the value of x in the first equation we get,
⇒ y + 4y = 1
⇒ 4y = 1
⇒ y = 1/4
∴ x = y = 1/4
Problem 4: Example: Solve the nonlinear equation x+2y = 1 and x = 2
Solution:
Given, x+2y = 1
x = 2
By putting the value of x in the first equation we get,
⇒ 2+ 2y = 1
⇒ 2y = 1
⇒ y = 1/2
∴ y=1/2