Question

The points [-5,1],[1,p], and [4,-2] are collinear if the value of p is ?

Answer 1

Answer:

collinear means all the points low on the same line,

that means all slopes are equal,

for (-5,1),(4,-2),

m1=(y2-y1)/(x2-x1),

=>m1=(-2-1)/(4-(-5))=(-3)/9

=>m1=-1/3.

then m2 for (1,p),(4,-2) is also (-1/3),

=>-1/3=(-2-p)/(4-1),

=>-1/3=(-2-p)/3,

therefore, -2-p=-1,

=>p=-1.