Find value of r when given ordered pairs

Question

Given the ordered Pairs find the value of R that makes the slope equal to given value. (5,3) and (6,r),m=-1

Answer 1

Hi Gab,

To solve this problem, you will want to use your slope formula.

(y2 - y1)/(x2 - x1) = m

Let (5, 3) = (x1, y1) and let (6, r) = (x2, y2)

Now plug the values into the slope equation

(r - 3)/(6 - 5) = -1/1 (I like to set this up as a proportion because then you can cross multiply. Sometimes m will equal a fraction and then you will not need to put it over "1".)

Now, Cross multiply

1(r - 3) = -1(6 - 5) Simply

r - 3 = -1(1)

r - 3 = -1 (add 3 to both sides)

+3 +3

r = 2.

I hope this helps.

Answer 2

Hi Gab!

Slope can be thought of as the rise/run , or the change in y / change in x

We can set up a slope formula [(y2-y1)/(x2-x1)] using the points given, (5,3) and (6,r):

(r-3)/(6-5) = m

Simplified:

(r-3)/1 = m or r-3 = m

Now we take into account that m=-1

r-3 = -1

By adding 3 to each side we are able to isolate r, finding that:

r = 2