# Determining the value of r?

determine the value of r so the line that passes through each pair of points has the given slope? thats the directions, (1,r),(1,-4),m=-5, (-2,1),(r,4),m=3/5, (-1,3),(-3,r)m=-3? pleez explain in full detail how to answer those three questions!!PLEEEZ HELP ME!!!

### 1 Answer

- GrampedoLv 71 decade agoBest Answer
No.2

(-2,1),(r,4), m=3/5

Slope =m = rise/run

3/5=(4-1)/(r-(-2))

3/5=3/(r+2)

3(r+2)=3(5)

3r+6=15

3r=9

r=3

N0.3

(-1,3),(-3,r), m= -3

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

-3=(r-3)/-2

(-3)(-2)=r-3

6=r-3

9=r

No.1

I've left this one to the last because, as worded, it is not possible to

solve. There is a contradiction.

m=rise/run,

For (1,r),(1,-4), m=5

5=(-4-r)/1-1)

5=(-4-r)/0

Division by zero is not allowed

Therefore slope cannot be =5

Check the co-ordinates. If they are as you say, no solution. If there is

an error, solve as shown for Nos. 2 and 3.

As it stands, the coordinates (1,r)(1,-4) lie on a horizontal line r+4 units

above (or below, if r<-4) the x-axis