How do you find the value of r so the line that passes through each pair of points has the given slope.

## (-2,r), (6,7), m=1/2. How do you find r?

# 2 Answers

You have two points, which can be labeled (x_{1,} y_{1}) and (x_{2}, y_{2}).

The formula for the slope between two points is m = (y_{2} - y1 )/(x_{2} - x_{1}).

We can fill in the pieces:

1/2 = (7 - r)/(6 - (-2))

0r (7 - r)/(6 + 2) = 1/2

(7 - r)/8 = 1/2

Now multiply both sides by 8 to clear 8 from the denominator on the left:

(7 - r) = 8(1/2)

7 - r = 4

**r = 3**

slope is rise over run

so

r-7 = 1

-2-6 2

we start by simplifying as much as we can

r-7 = 1

-8 2

next we get rid of the denominators by cross multiplying. we multiply the bottoms by the tops on the other side of the equation

2(r-7)=-8*1

then simplify

2(r-7)=-8

then we distribute the 2 a(b+c)=ab+ac

2r-2*7=-8

2r-14=-8

then cancel the 14 by adding 14 to both sides

2r-14+14=-8+14

2r=6

then cancel the 2 by dividing both sides by 2

2r/2=6/6

r=3

so r has to be 3

did you understand if you have any questions please comment.