**Various Equation Forms of a Straight Line
**by

Larry E. Dodd

www.101science.com

The equation of a straight
line can be written in three different forms. Below are three equation forms and
proof they are all equal to each other.

y – y_{1} = m(x - x_{1}) :: **Point slope equation
form.**

Where m=slope and y – y_{1 }and x - x_{1 }are
points on the line

y = mx + b
:: **Slope Intercept form. **

Where m=slope, b=y interecpt when x=0

Ax + By = C :: **Standard form. **

Example:

Lets take the straight line that crosses two
(x, y) points of (3,2) and (8,4). The equations for this line are shown
below. All three forms of the equation represent the same straight line
shown in the graph.

y - 2 = 2/5(x-3) ::
**Point slope form****
**y = 2/5x + .8
::

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