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Home » The equation of the line passing through the point (1, 2) and perpendicular to the line x + y + 1 = 0 is A. y – x + 1 = 0 B. y – x – 1 = 0 C. y – x + 2 = 0 D. y – x – 2 = 0
The equation of the line passing through the point (1, 2) and perpendicular to the line x + y + 1 = 0 is A. y – x + 1 = 0 B. y – x – 1 = 0 C. y – x + 2 = 0 D. y – x – 2 = 0
CBSE | Class 11 | maths | ncert exemplar | Straight Lines
The equation of the line passing through the point (1, 2) and perpendicular to the line x + y + 1 = 0 is A. y – x + 1 = 0 B. y – x – 1 = 0 C. y – x + 2 = 0 D. y – x – 2 = 0

The correct option is option(B)- y – x – 1 = 0

line passing through the point (1, 2)

And perpendicular to the line x + y + 1 = 0

Let the equation of line L  is

    \[x\text{ }-\text{ }y\text{ }+\text{ }k\text{ }=\text{ }0\text{ }\ldots \text{ }\left( i \right)\]

Since, L is passing through the point (1, 2)

    \[\begin{array}{*{35}{l}} \therefore ~1\text{ }-\text{ }2\text{ }+\text{ }k\text{ }=\text{ }0 \\ \Rightarrow ~k\text{ }=\text{ }1 \\ \end{array}\]

Putting the value of k in equation (i), we get

    \[\begin{array}{*{35}{l}} x\text{ }-\text{ }y\text{ }+\text{ }1\text{ }=\text{ }0 \\ Or\text{ }y\text{ }-\text{ }x\text{ }-\text{ }1\text{ }=\text{ }0 \\ \end{array}\]

 

i

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