Q8 of 51 Page 10

Find the value of x for which the points(x, -1), (2, 1) and (4, 5) are collinear.


Let the points be A(x, -1), B(2, 1) and C(4, 5)

Now as the points are collinear, therefore

mAB = MBC

Now mAB = =

and mBC = = = 2

As mAB = mBC

We have = 2

2 = 2(2 – x) = 4 – 2x

or 2x = 4 – 2

⇒ 2x = 2 ⇒ x = 1

More from this chapter

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6
Without using the Pythagoras theorem, show that the points(4, 4), (3,5) and (-1, -1) are the vertices of a right angled triangle.

7
As shown in the figure below, the given line makes an angle of 300 with the positive direction of y-axis in anticlockwise direction.

9
Without using distance formula, show that points(-2, -1), (4, 0), (3, 3) and (-3, 2) are the vertices of a parallelogram.

10
Find the angle between x-axis and the line joining the points(3, -1) and (4, -2).