What is the fundamental idea of linear equation

A linear equation is an equation with only one solution. It means that you only have one value of y for every value of x of an equation.

It is in the form of y = ax + b, where a and b are real numbers.

Ex. 1:

y = 4x + 5

let x = 3, and substitute

y = 4 (3) + 5

y = 12 + 5

y = 17

Moreover, the graph of a linear equation is a line graph.