A linear equation is a equation which can be written in the form , ax+b=0 , x is a variable.

Also, a linear equation can also be written in two variables as of form, ax+by=0 here, x,y are variables.

The system of linear equation is when there are two or more than two linear equations are involved like,

2x−3y=8x+7y=23

So, we have two linear equation in two variables x and y.

Also, the linear equation has variables with the max power of variables as 1 then its a linear equation.

So, a system of linear equation with one or two variable can be written as two or more than two linear equations together.