Question

If A(3, 4), B(7, 2), C (x,y) are collinear, then

(a) x+5y+17=0
(b) x+5y+13=0
(c) x-5y+17=0
(d) none of these​

Answer 1

Answer:

if the points are collinear then area of triangle is equal to zero.

(d) NOTA

x+2y-4=0

Answer 2

Coordinate Geometry

(d) None of these

A(3, 4), B(7, 2), C (x, y) are collinear, which means,

$\begin{vmatrix} 3 & 4 &1 \\ 7 & 2 &1 \\ x & y &1\end{vmatrix}=0$

$\implies 3(2-y)-4(7-x)+1(7y-2x)=0\\\\\implies (6-3y-28+4x+7y-2x)=0\\\\\implies (2x+4y-22)=0\\\\\implies x+2y-11=0$

Hence, x+2y-11=0 will be required answer.