The equation of a straight line parallel to the x-axis is given by
Answer & explanation
Correct answer: option 4
Equation of straight line parallel to x−axis is
$\frac{x-a}{1}=\frac{y-b}{0}=\frac{z-c}{0}$
because $l=\cos \alpha=1, m=\cos \beta=\cos \frac{\pi}{2}=0, n=\cos \gamma=0$