Question 890589
find the equation of a line passing through the points (-3,6) and (1,2)

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To find the slope, we use the change in y over change in x formula. {{{ (6-2) / (-3-1) }}} = {{{ (-4/4) }}} = (-1)

Plug that into the slope-intercept formula: {{{ y= (-1)x+b }}} We can just write this as {{{ y= (-x)+b }}}

Pick one of the points (it doesn't really matter) and plug that into the formula. I want to use (1,2). 

{{{ 2=(-1)(1)+b }}} 

{{{ 2=(-1)+b }}}

{{{ b=(3) }}}

So now the formula looks like {{{ y=(-x)+3 }}}

We can plot this formula to make sure that the points are on the graph. 

 {{{ graph( 300, 200, -10, 10, -10, 10, y=(-x)+3) }}}