Theory:

Straight line:
 
An equation of first degree and of the form \(ax + by + c = 0\) is called as "straight line" in \(xy\) - plane.
 
Here, \(x\) and \(y\) are variables,
 
\(a\), \(b\) and \(c\) are real numbers, and atleast one of \(a\), \(b\) are non - zero.
 
The graphical representation of a straight line is:
 
1.png
Equation of coordinate axes
The \(X\) - axis and \(Y\) - axis together form the graph, and they are called the cartesian plane or the coordinate axes.
 
A point on the coordinate axes:
 
If a point lies on the \(x\) - axis, then the coordinate of the point is \((x,0)\).
 
The equation of a point lying on the \(x\) - axis is \(y = 0\).
 
Consider plotting the points on the \(x\) - axis and observe the equation we get:
 
2.png
 
Similarly, if a point lies on the \(y\) axis, then the coordinate of the point is \((0,y)\).
 
The equation of the point on the \(y\) axis is \(x = 0\).
 
Consider plotting the points on the \(y\) axis and observe the equation we get:
 
3.png