By using the concept of equation of a line, prove that the three points (3, 0), (– 2, – 2) and (8, 2) are collinear
By using the concept of equation of a line, prove that the three points (3, 0), (– 2, – 2) and (8, 2) are collinear

On the off chance that we need to demonstrate that the given three focuses

    \[\left( \mathbf{3},\text{ }\mathbf{0} \right),\text{ }\left( \text{ }\mathbf{2},\text{ }\text{ }\mathbf{2} \right)\text{ }\mathbf{and}\text{ }\left( \mathbf{8},\text{ }\mathbf{2} \right)\]

 are collinear, then, at that point, we need to likewise demonstrate that the line going through the focuses

    \[\left( \mathbf{3},\text{ }\mathbf{0} \right)\text{ }\mathbf{and}\text{ }\left( \text{ }\mathbf{2},\text{ }\text{ }\mathbf{2} \right)\]

additionally goes through the point

    \[\left( \mathbf{8},\text{ }\mathbf{2} \right).\]

 

By utilizing the equation,

 

The condition of the line going through the focuses

    \[\left( \mathbf{x1},\text{ }\mathbf{y1} \right)\text{ }\mathbf{and}\text{ }\left( \mathbf{x2},\text{ }\mathbf{y2} \right)\]

is given by

NCERT Solutions for Class 11 Maths Chapter 10 – Straight Lines image - 32

    \[-\text{ }\mathbf{5y}\text{ }=\text{ }-\text{ }\mathbf{2}\text{ }\left( \mathbf{x}\text{ }-\text{ }\mathbf{3} \right)\]

    \[-\text{ }\mathbf{5y}\text{ }=\text{ }-\text{ }\mathbf{2x}\text{ }+\text{ }\mathbf{6}\]

    \[\mathbf{2x}\text{ }\text{ }\mathbf{-5y}\text{ }=\text{ }\mathbf{6}\]

On the off chance that

    \[\mathbf{2x}\text{ }\text{ }\mathbf{-5y}\text{ }=\text{ }\mathbf{6}\]

 goes through

    \[\left( \mathbf{8},\text{ }\mathbf{2} \right),\]

    \[\mathbf{2x}\text{ }\text{ }\mathbf{-5y}\text{ }=\text{ }\mathbf{2}\left( \mathbf{8} \right)\text{ }\text{ }\mathbf{-5}\left( \mathbf{2} \right)\]

    \[=\text{ }\mathbf{16}\text{ }-\text{ }\mathbf{10}\]

    \[=\text{ }\mathbf{6}\]

    \[=\text{ }\mathbf{RHS}\]

The line going through the focuses

    \[\left( \mathbf{3},\text{ }\mathbf{0} \right)\text{ }\mathbf{and}\text{ }\left( \text{ }\mathbf{2},\text{ }\text{ }\mathbf{2} \right)\]

 likewise goes through the point

    \[\left( \mathbf{8},\text{ }\mathbf{2} \right).\]

 

Thus demonstrated. The given three focuses are collinear.