Question

What is equation of a line parallel to the y-axis and 3 units to the left of it ?

Answer 1

answer is x=3
by the coordinate geonetry

Answer 2

Line ∥ to y - axis is written as : x = a

according to question,

Line passes through ( - 3 , 0 )

Or
Line is at distace of - 3 from y - axis ,

So Equation of line is : x = -3

x + 3 = 0