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Equations of Lines

The next thing is to remember how to find the equation of a line given a point and a slope.

If we have a point, ( x1 , y1 )and a slope, m, here's our formula:
   
y - y1 = m( x - x1 )

You'll be using this a lot, so let's run through a couple of examples...

Find the equation of the line that passes through the point 
( 4 , - 3 )with a slope of -2:

y - y1 = m( x - x1 ) ... y - ( -3 ) = -2( x - 4 ) ... y + 3 = -2x + 8 ... be careful here! ... y = -2x + 5