Which of the following equations represent a line parallel to y-axis?

Correct option is B

Concept Used:
A line parallel to the y-axis is a vertical line.
The general equation of a vertical line is x = k, where k is a constant.
Solution:
Option A: y = 3 
Form: y = k  (where k = 3).
Interpretation: This is a horizontal line parallel to the x-axis, not the y-axis.
Conclusion: Not parallel to the y-axis.
Option B: x + 3 = 4 - 2x 
x + 3 = 4 - 2x
x + 2x = 4 - 3
3x = $$1 \implies x = \frac{1}{3}$$​
Form: x =$$\frac{1}{3}.$$​
Conclusion: Parallel to the y-axis.
Option C: 2x + y = 0 
Rewrite in slope-intercept form:
y = -2x
Interpretation: This is a line with a slope of  -2 , which is neither horizontal nor vertical.
Conclusion: Not parallel to the y-axis.
Option D: y - 2 = 1 
$$y - 2 = 1 \implies y = 3$$​
Form: y = 3.
Interpretation: This is a horizontal line parallel to the x-axis, not the y-axis.
Conclusion: Not parallel to the y-axis.
The equation that represents a line parallel to the y-axis is Option B x + 3 = 4 - 2x , which simplifies to x $$= \frac{1}{3}.$$​