Answer:
k = 11
Step-by-step explanation:
Given the points are collinear then the slopes between consecutive points are equal.
Using the slope formula
m =
with (x₁, y₁ ) = (5, 1) and (x₂, y₂ ) = (1, - 1)
m = =
=
Repeat with another 2 points and equate to
with (x₁, y₁ ) = (1, - 1) and (x₂, y₂ ) = (k, 4)
m = , then
=
( cross- multiply )
k - 1 = 10 ( add 1 to both sides )
k = 11