Question

The points (-5,1),(,p) and (4,2) are collinear if the value of p is​

Answer 1

x1 = -5

x2= 1

x3= 4

y1= 1

y2= p

y3= -2

For the points to be collinear

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

-5{ p-(-2)} +1(-2-1) + 4(1- p)= 0

-5( p+2)+1(-3) +4(1- p)= 0

-5p -10 -3+4- 4p=0

-9p -9= 0

-9p= 9

p= 9/-9

p= -1