Question

Equation of the straight line perpendicular to the line x – y + 5 = 0, through the point of intersection the y-axis and the given line …

(a) x – y – 5 = 0 

(b) x + y – 5 = 0 

(c) x + y + 5 = 0 

(d) x + y + 10 = 0

Answer 1

(b) x + y – 5 = 0

x – y + 5 = 0 ⇒ put x = 0, y = 5 

The point is (0, 5) 

Equation of a line perpendicular to 

x – y + 5 = 0 is x + y + k = 0 

This passes through (0, 5) 

k = -5 

x + 7 – 5 = 0