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))(y+3)=3(x4)

or

(y - color(red)(3)) = color(blue)(-3)(x - color(red)(2))(y3)=3(x2)

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))m=y2y1x2x1

Where mm is the slope and (color(blue)(x_1, y_1)x1,y1) and (color(red)(x_2, y_2)x2,y2) 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=3324

m = (color(red)(3) + color(blue)(3))/(color(red)(2) - color(blue)(4))m=3+324

m = 6/-2m=62

m = -3m=3

The point-slope formula states: (y - color(red)(y_1)) = color(blue)(m)(x - color(red)(x_1))(yy1)=m(xx1)

Where color(blue)(m)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))