Question

The equation of the straight line passing through the points (3, 2) and perpendicular to the line y = x is
(a) x – y = 5
(b) x + y = 5
(c) x + y = 1
(d) x – y = 1

Answer 1

Slope of y = x is 1.
The slope of line perpendicular to y = x is −1
Also this line passes through (3, 2)
i.e. y − 2 = − 1 (x – 3) is the required equation of the line.
i.e. y − 2 = − x + 3
i.e. y + x = 5
i.e. x + y = 5 is the required equation of the line.

Hence, the correct answer is option B.