Question

For what value of p, are the points (-3,9),(2,p) and (4,-5) collinear?

Answer 1

Hi !

x₁ = -3   
x₂ = 2
x₃ = 4

y₁ = 9
y₂ = p
y₃ = -5

For the points to be collinear :-

x₁(y₂  -y₃) + x₂(y₃ - y₂) + x₃(y₁ - y₂) = 0

-3( p - (-5)) + 2(-5 - 9) + 4( 9 - p) = 0

-3( p + 5) + 2(-14) + 4( 9 - p) = 0

-3p - 15 - 28 + 36 - 4p = 0

-7p - 7 = 0

-7p = 7

p = 7/-7

p = -1

Answer 2

Answer:

I think

p= -1 (ans).............