Q. which one is graph of inequality y<2x+3
the shaded part is the part that denotes the inequality, i guess u already know that. if there's a straight line between the shaded part and the white part, there should be a = sign in the equation....you dont see any '=' in the equation, do you? in that case, you can just eliminate B.
now, the best way is to take a (x,y) pair. and the easiest to work with is the (0.0) pair. substitute the values of x and y here.
0<2.0+3
or, 0<3 which is totally true
(0,0) lies in the shaded part of C, so C is the answer.
sometimes, you might also have to check some other pairs (1,1) or something else too, just to be sure.
if you'r wondering whether A is correct or not, take a point that lies in the shaded part, lets say it is (-2,4) (its in the shaded part, check out)
4<2.(-2)+3
or, 4<-4+3
or, 4<-1
apparently, 4 can never be less than -1. so there you go...its not A, not B...its C.