Question

The points (-5,r) and (2,13) lie on a with slope 3 find the missing coordinate r

Answer 1

r = - 8

Explanation:

calculate the slope m using the slope formula , then equate to 3

m =
`(y_(2)-y_(1) )/(x_(2)-x_(1) )`

with (x₁, y₁ ) = (- 5, r ) and (x₂, y₂ ) = (2, 13 )

m =
`(13-r)/(2-(-5))` =
`(13-r)/(2+5)` =
`(13-r)/(7)`

then equating gives

`(13-r)/(7)` = 3 ( multiply both sides by 7 )

13 - r = 21 ( subtract 13 from both sides )

- r = 8 ( multiply both sides by - 1 )

r = - 8