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Q : 8         Find the value of x for which the points  (x,-1),(2,1) and  (4,5)  are collinear.

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Point is collinear which means they lie on the same line by this we can say that their slopes are equal
Given points are A(x,-1) , B(2,1) and C(4,5)
Slope = m = \frac{y_2-y_1}{x_2-x_1}
The slope of AB = Slope of BC
\frac{1+1}{2-x}= \frac{5-1}{4-2}
\frac{2}{2-x}= \frac{4}{2}\\ \\ \frac{2}{2-x} = 2\\ \\ 2=2(2-x)\\ 2=4-2x\\ -2x = -2\\ x = 1
Therefore, the value of x is 1

Posted by

Gautam harsolia

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