What can be said regarding a line if its slope is i. positive ii. zero iii negative?

Explanation

(i) If the slope of the line is zero it means
M = tan θ
M = tan 0
Since, m = 0
So,The line is parallel to x - axis.
(ii) If the slope of the line is positive it means Since θ is an acute So, The line makes an acute angle with the positive x - axis.
(iii) If the slope of the line is positive it means Since, θ is an obtuse <>So, The line makes an obtuse angle with positive x - axis.