- An equation is called a Linear equation in one variable or an equation of degree one in one variable, if only a single variable with degree one occurs in the equation.
- An equation is called a Linear equation in one variable or an equation of degree one in one variable, if only a single variable with degree one occurs in the equation.
Example
2x+3=4
- Coordinates

- The co-ordinate of the foot of the perpendicular draw on the x-axis from the given point P is x-coordinate of the point P ('a'). Similarly 'b' is the y-coordinate of the point P.
- The coordinate of P are (a, b).
- The ordered pair of the coordinates (a, b) denotes the position of the point P.
- Plotting of a point
In a graph, a point say (2,2) is plotted as follows:
Start from centre 'O' move 2 units towards right on the x-axis i.e., OX and 2 units up words along the perpendicular to the x-axis (XOX'). Thus the position of 'P' is plotted.Linear equations in two variables
A linear equation of the form ax + by + c = 0 where a = 0, b ยน 0 is called a linear equation in two variables.
Example
x+2y+4=0
