How do you write an equation in point slope form given (8,3), (-1/3,-2)?

1 Answer
Mar 21, 2017

See the entire solution process below:

Explanation:

First, we need to determine the slope f the line. 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 points in the problem gives:

#m = (color(red)(-2) - color(blue)(3))/(color(red)(-1/3) - color(blue)(8)) = (-5)/(color(red)(-1/3) - color(blue)(24/3)) = ((-5)/1)/((-25)/3) = (-5 xx 3)/(1 xx -25) =#

#(-1 xx 3)/(1 xx -5) = (-3)/-5 = 3/5#

Now, we can use the point-slope formula to write the equation. 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 slope we calculated and the first point from the problem gives:

#(y - color(red)(3)) = color(blue)(3/5)(x - color(red)(8))#

Or. we can substitute the slope we calculated and the second point from the problem giving:

#(y - color(red)(-2)) = color(blue)(3/5)(x - color(red)(-1/3))#

#(y + color(red)(2)) = color(blue)(3/5)(x + color(red)(1/3))#