In math geometry, the lines and angles are important tools. A line is a collection of points along a straight path; it extends in both the directions and has no endpoints. It has no definite length.
Two lines are said to be parallel if they don't have any intersecting points. Parallel lines do not meet. Two lines are said to be perpendicular if the angle formed between then is 900.
The general equation of a straight line is y = mx + c, where m is the gradient, and y = c is the value where the line cuts the y-axis. This number c is called the intercept on the y-axis. The equation of a straight line with gradient m and intercept c on the y-axis is y = mx + c.
y = m x + b.
It's called the equation of a straight line, because if we plot the points that satisfy this equation on a graph of y versus x then, the points all lie on a straight line.
A typical use of a linear function is to convert from one set of units to another. A simple example is if i is a distance measured in inches and c is the same distance measured in centimetres; then c = 2.54 i. It is just scaling. A more complicated example is if c is a temperature measured in Celsius degrees and f is the same temperature measured in Fahrenheit degrees; then f = 1.8 c + 32. It is scaling and a shift.