Question

The points (-11, r) and (-7,5) lie on a line with slope

3
4
Find the missing coordinate r.

Answer 1

r = 2

Explanation:

Calculate slope m using the slope formula and equate to
`(3)/(4)`

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

with (x₁, y₁ ) = (- 11, r) and (x₂, y₂ ) = (- 7, 5)

m =
`(5-r)/(-7+11)` =
`(5-r)/(4)` =
`(3)/(4)` ( multiply both sides by 4 to clear the fractions )

5 - r = 3 ( subtract 5 from both sides )

- r = - 2 ( multiply both sides by - 1 )

r = 2