The points (-4, r) and (4, -1) lie on a line with slope -1. find the missing coordinate r.

7

Step-by-step explanation:

The formula for slope is where is the slope and are points on the line.

We can use that formula but I like to line my points up vertically and subtract and then put 2nd difference over 1st difference.

(-4,r)

minus

(4,-1)

--------

-8  r-(-1)

So we have:

Multiply both sides by -8:

Subtract 1 on both sides:

.

Let's check:

(-4,7)

minus

(4,-1)

-------

-8 8

So the slope is 8/-8=-1 which is what we wanted.

So the value for r being 7 has been checked and verified.

step-by-step explanation:

i think something is missing in your question because y-1=(x-12) would not pass through the point (-4,-3). because if you replace x by -4 your are supposed to find y=-3 which is not the case her. if you replace x by -4 you find =-15.

i assume the right equation is y-1=1/4*(x-12) because this one is passing through both your points (if you are interested to know how i found that out i can tell you).

in this equation if i replace x by -4 i find y=-3 and if i replace x by 12, i find y=1 so the line representing this equation is passing through those 2 points.

then the standard form of the equation is finding an expression of y in function of x

y-1=1/4*(x-12)

y=x/4-3+1

y=x/4-2

hope that .

do you confirm there was a mistake in the question?