Question 202570
The  easiest  way  to   define  which  side  of  the  line  is  the  "area  of  interest" is  to  use  test  points.

Just  pick  a  point  on  either  side  of  the  line,  substitute  into  inequality,  and  see  if  it  is  true,,,,,or  not.  The  true  side  is  the  area  of  concern

In  this  case,  line  goes  thru  (0,1)  so  lets  pick (0,2)  which  is  above  the  line.   y>= 2x+1,  subst,, 1>= 2(0)+1,,,true  statement,  1=1 so  this  is  correct  side.

If  we  chose  a  point  on  the  other  side  of  the  line(bottom), like  (0,0)
y>=2x+1,  0>= 2(0) +1,,,0>=1,,,not  true.  The  area  is  on  the  other  side  from  this  point.
.
Sometimes  it  is  obvious  that  area  is  above  or  below,,to  right  or  left,,,,but  a  quick  test  point  is  good  confirmation.