Animated Mathematics

Linear Equations: Content


Straight lines in every day life, the example of a moving car.

Gradient Intercept Form of a Straight Line

The general equation of a straight line has the from y=mx+c. You can plot the line by generating two points.

Point on the Line?

A point can be on, above, or below a line; and this can be investigated algebraically.

Axes Intercepts

The intercept coordinates of a straight line with the axes can be estimated visually or found exactly using algebra.


The gradient of a line is the rise over run. The gradient can be found of a line passing through two points.

Vertical and Horizontal Lines

The equations of vertical and horizontal lines are simple since the m-value have special values. The gradient of a horizontal line is zero, whereas the gradient of a vertical line is infinity.

Parallel Lines

Parallel lines never intersect and have the same gradient.

Perpendicular Lines

Perpendicular lines intersect to define a 90 degree intersection angle.

Lines Intersection

The intersection point of two lines can be estimated by plotting the lines, and the exact coordinate can be found algebraically.