Arithmetic Course/Linear Function

Linear Function
Linear Function is a function of a Straight Line

Straight Line goes through point (0,0)
For every x there is y = x
 * x | y
 * -2 | -2
 * -1 | -1
 * 0 | 0
 * 1 | 1
 * 2 | 2

If f(x) = y Then f(x) represents a Straight Line through point (0,0) with Slope equals 1

Straight Line goes through two points
If there is a Straight Line goes through 2 points (xo,yo), (x,y)
 * $$m = \frac{y - y_o}{x - x_o} $$
 * $$y = y_o + m (x - x_o) $$

Straight Line goes through Two Intercept Points

 * $$\frac{x}{a} + \frac{y}{b} = 1$$

When
 * x = 0 y = b
 * y = 0 x = a

Function $$f(x,y) = \frac{x}{a} + \frac{y}{b} = 1$$ of a Straight Line that cuts the x axis at (0,a) and the y axis at (0,b)