How do you write the equation in point slope form given (4,-3) , (2,3)?

1 Answer
Jan 25, 2017

#(y + color(red)(3)) = color(blue)(-3)(x - color(red)(4))#

or

#(y - color(red)(3)) = color(blue)(-3)(x - color(red)(2))#

Explanation:

First, determine the slope.

The slope can be found by using the formula: #m = (color(red)(y_2) - color(blue)(y_1))/(color(red)(x_2) - color(blue)(x_1))#

Where #m# is the slope and (#color(blue)(x_1, y_1)#) and (#color(red)(x_2, y_2)#) are the two points on the line.

Substituting the values from the problem gives:

#m = (color(red)(3) - color(blue)(-3))/(color(red)(2) - color(blue)(4))#

#m = (color(red)(3) + color(blue)(3))/(color(red)(2) - color(blue)(4))#

#m = 6/-2#

#m = -3#

The point-slope formula states: #(y - color(red)(y_1)) = color(blue)(m)(x - color(red)(x_1))#

Where #color(blue)(m)# is the slope and #color(red)(((x_1, y_1)))# is a point the line passes through.

Substituting the values from one of the points in the problem and the slope we calculated gives:

#(y - color(red)(-3)) = color(blue)(-3)(x - color(red)(4))#

#(y + color(red)(3)) = color(blue)(-3)(x - color(red)(4))#

Substituting the values from one the other points in the problem and the slope we calculated gives:

#(y - color(red)(3)) = color(blue)(-3)(x - color(red)(2))#