When solving a 2 step inequality, when do you flip the inequality sign, i keep getting these questions wrong, pls , i mark ! !

You flip the signs when you are dividing by a negative value.
-2x+3>15
-2x>15-3
-2x>12
x<12/-2
x<-6
Now to test this
Try putting x in the original equation when it is -5.
-2(-5)+3>15
10+3>15
13>15
This is false because our answer says x is less than -6.
Now any value less than -6 will work so let's go with -7.
-2(-7)+3>15
14+3>15
17>15
This result is True.
Hope this helps out!