What is (-12,8) & (9,1) in slope-intercept form?

Answer 1

Hello Marcelle, here is an idea to solve this problem.

A line passing two given points can be represented by two point form, say

(y-5) / (3-5) = (x+6) / (9+6)

which is a line passing two points (-6, 5) and (9, 3).

We can always rewrite the above form into a form y = kx + b, which is a slope-intercept form.

Here is what we can do with our example above,

(y-5) / (-2) = (x+6) / 15 ==> y-5 = -2/15 (x+6) ==> y = -2/15x -12/15+5

That is,

y = -2/15x + 21/5

a slope-intercept form

Answer 2

I found the slope of the line using the formula for slope [(y-y)/(x-x)]. (1-8)/(9- -12)= -7/21= -1/3

Using the slope intercept form of a line (y=mx+b), I use the slope to rewrite the formula by substituting -1/3 for the m.

y= -1/3x + b I then use one of the points given for x and y values to also substitute into the equation to find b.

(9,1)

1= -1/3(9) + b

1= -3 + b

b=4

Now I will substitute 4 for the b to get the equation y= -1/3x+ 4