Question

Find the equation of a line passing through (2, –3) and inclined at an angle of 135º with the positive direction of x-axis.

Answer 1

Here, m = slope of the line = tan 135º = tan (90º + 45º) = – cot 45º = –1, x₁ = 2, y₁ = –3 

So, the equation of the line is y – y₁ = m (x – x₁) 

i.e. y – (–3) = –1 (x – 2) or y + 3 = –x + 2 or x + y + 1 = 0