Question

Which of the following is/are true for the eqaution $ax+by+c=0$?

(More than one correct answer)

• A. If a=0, the line is parallel to y-axis
• B. If a=0, the line is parallel to x-axis
• C. If b=0, the line is parallel to y-axis
• D. If b=0, the line is parallel to x-axis

Answer 1

Answer: (B), (C)

The correct options are
B If a=0, the line is parallel to x-axis
C If b=0, the line is parallel to y-axis

In the equation $ax+by+c=0$, if we substitute a=0, then we get $y=\frac{-c}{b}$. This means the y-coordinate is fixed because a, b and c are constants. But the x-coordinate can be anything since a=0 and anything multiplied by 0 is always zero. Therefore in this case the line will be parallel to the x-axis

Now similarly, when b=0 then the line will be parallel to the y-axis.