<em>Hope</em><em> </em><em>this</em><em> </em><em>will</em><em> </em><em>help</em><em> </em><em>u</em><em>.</em><em>.</em><em>.</em><em>:</em><em>)</em>
If the points are scattered it’s no correlation
Given:


To find:
The obtuse angle between the given pair of straight lines.
Solution:
The slope intercept form of a line is
...(i)
where, m is slope and b is y-intercept.
The given equations are


On comparing these equations with (i), we get


Angle between two lines whose slopes are
is

Putting
and
, we get



Now,
and 
and 
and 
, so it is an obtuse angle and
, so it is an acute angle.
Therefore, the obtuse angle between the given pair of straight lines is 120°.