Question

The value of P for which the points (-5,1),(1,-1) and (P,-2) are collinear, is​

Answer 1

The value of P for which the points (-5,1),(1,-1) and (P,-2) are collinear, is

Answer 2

Given,

The three points are (-5,1),(1,-1) and (P,-2).

To find,

The value of P for which the three points will be collinear.

Solution,

We have to apply the formula of the area of the triangle. For the value of P which makes the three points collinear, will also produce zero value of the area of triangle.

For better calculations,

A = (-5,1) = X1,Y1

B = (1,-1) = X2,Y2

C = (P,-2) = X3,Y3

Now, according to the previously mentioned data

½ [X1 (Y2-Y3) + X2 (Y3-Y1) + X3 (Y1-Y2)] = 0

½ [-5 (-1+2) + 1 (-2-1) + P (1+1)] = 0

½ [ -5 -3 + 2P] = 0

½ [-8+2P] = 0

-4 + P = 0

P = 4

Hence, the value of P will be 4.