A line is a one-dimensional infinite set of points that extend into two directions without curvature.

It may also be seen as a "double-sided" ray.

In coordinate geometry, a line is defined in the Cartesian coordinate plane as the infinite set of points where each point satisfies a given equation in the form: $ Ax + By = C $, where A, B and C are constants.

Furthermore, the equation of a 'line' (parallel or perpendicular) can be found from a graph in which equation is equal to $ y=mx+c $ where $ mx $ denotes the gradient, and $ +c $ denotes the $ y-axis $ intercept.

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