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Using Determinants, Find the Equation of the Line Joining the Points (1, 2) and (3, 6) - Mathematics

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Question

Using determinants, find the equation of the line joining the points

(1, 2) and (3, 6)

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Solution

GivenA  =  (1, 2) and B  =  (3, 6)

Let the point P be (xy).  So,

Area of triangle ABP = 0

\[\Rightarrow ∆ = \frac{1}{2}\begin{vmatrix}1 & 2 & 1 \\ 3 & 6 & 1 \\ x & y & 1\end{vmatrix} = 0\] 
\[ \Rightarrow 1\left( 6 - y \right) - 2\left( 3 - x \right) + 1\left( 3y - 6x \right) = 0\] 
\[ \Rightarrow 6 - y - 6 + 2x + 3y - 6x = 0\] 
\[ \Rightarrow 2y - 4x = 0\] 
\[ \Rightarrow y = 2x\]

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Chapter 6: Determinants - Exercise 6.3 [Page 72]

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RD Sharma Mathematics [English] Class 12
Chapter 6 Determinants
Exercise 6.3 | Q 12.1 | Page 72

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