x + 3 = 0 is the equation of a line

x + 3 = 0

⇒ x = 0 – 3

⇒ x = – 3

Therefore, the value of x co – ordinate will be – 3. Hence, the line will pass through ( – 3,0).

Since, the value of x = – 3 therefore, it will pass through all values of y while x will remain constant. Hence, the line will be parallel to y-axis.