Question

If the line ax + by + c = 0 is such that a = 0 and b, $c\ne 0$ then the line is perpendicular to

• A. x-axis
• B. y-axis
• C. x + y =1
• D. x = y

Answer 1

Answer: (B)

y-axis

When $a=0$ then the line equation becomes $by+c=0$ or $y=-\frac{c}{b}$
Equations of the form $y=k$ are parallel to x-axis. This also means that they are perpendicular to $y-$ axis as $x-$ axis and $y-$axis are perpendicular to each other.