# For What Value of X Are the Points A(-3, 12), B(7, 6) and C(X, 9) Collinear. - Mathematics

For what value of x are the points A(-3, 12), B(7, 6) and C(x, 9) collinear.

#### Solution

A(-3,12) ,B (7,6) and C(x,9) are the given points. Then:

(x_1=-3,y_1=12) , (x_2=7,y_2=6) and (x_3= x, y_3=9)

It is given that points A, B and C are collinear. Therefore,

x_1(y_2-y_3)+x_2(y_3-y_1) +x_3(y_1-y_2)=0

⇒ (-3)(6-9)+7(9-12)+x(12-6)=0

⇒(-3)(-3)+7(-3)+x(6)=0

⇒ 9-21+6x=0

⇒ 6x-12=0

⇒ 6x =12

⇒ x = 12/6=12

Therefore, when  x =2 , the given points are collinear

Concept: Area of a Triangle
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#### APPEARS IN

RS Aggarwal Secondary School Class 10 Maths
Chapter 16 Coordinate Geomentry
Q 15