Question

How do I put 2 points into point-slope form

ex- (-5,-4,) and (-7,4)

Answer 1

You want the equation of the line through those two points, written in point-slope form?

Answer 2

yes please

Answer 3

you have to find the slope first

Answer 4

Okay. You have two points, (-5, -4) and (-7, 4). We'll call those points
(x1, y1) and (x2, y2). Doesn't matter which point is which, so I'll choose (x1, y1) = (-5,-4).

Now, to write the equation in point-slope form, we need two things:

1) a point
2) the slope

We can pick either point for #1. For #2, we need to find the slope of the line going through those points. Here's the formula for the slope (m):

rise (y2 - y1)
m = ------- = --------
run (x2 - x1)

Basically, you just look at the left-most point, figure out how many points you go to the right (the run) and the up/down (the rise)

Answer 5

when you have the slope and a point, just plug the numbers into the formula:

y - y1 = m ( x - x1 )

where (x1, y1) is a point on the line, and m is the slope.

Answer 6

alright so the slope is -4

Answer 7

slope = (4 - (-4) / (-7 - (-5)
(4 + 4) / (-7 + 5)
8/-2
slope is -8/2 = -4
correct.

now use point slope formula
y - y1 = m(x - x1)
slope(m) = -4
you can choose either of your sets of points
(-5,-4) x1 = -5 and y1 = -4
now sub
y - (-4) = -4(x - (-5)
y + 4 = -4(x + 5) ===> point slope form

Answer 8

does that make sense to you ?

Answer 9

makes tons of sense. thank you

Answer 10

your very welcome :)