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
49*4=196+1=197/4
<span>8*3=24+3=27/8 </span>
<span>then make the denominator the same</span>
<span>multiply 197*2 and 4*2 = 394/8 </span>
<span>then 394/8 +27/8 =421/8 </span>
<span>u can either leave it here or in decimal form which would be 52.625 or in mixed numbers-52 5/8</span>
y - 2 = -3 (x+1)
point slope form
y-y1 = m(x-x1)
looking at the above equation
the slope is -3