Answer:
see explanation
Step-by-step explanation:
If the 3 points are collinear then the slope of PQ should equal the slope of QR
Calculate the slope m using the slope formula
m = (y₂ - y₁ ) / (x₂ - x₁ )
with (x₁, y₁ ) = P(- 1, 4) and (x₂, y₂ ) = Q(- 2, - 1)
[tex]m_{PQ}[/tex] = [tex]\frac{-1-4}{-2+1}[/tex] = [tex]\frac{-5}{-1}[/tex] = 5
Repeat using
(x₁, y₁ ) = Q(- 2, - 1) and (x₂, y₂ ) = R(1, 14)
[tex]m_{QR}[/tex] = [tex]\frac{14+1}{1+2}[/tex] = [tex]\frac{15}{3}[/tex] = 5
Since the slopes of the 2 segments are equal then the 3 points are collinear.
