DragonSlayer the first ones really easy , u don't have to do anything and just add 3 and 7 like this
-3x+2y+3+7
= -3x+2y+10 answer
and in the second one we will bring the like terms together ands solve like
4x+3+6x+4+2xy+3yx+2 ( so now out here we shall bring the like terms together !Note that as out here we have no equal sign so we will not change any signs while bringing the like terms together!
=4x+6x+3+4+2+2xy+3yx ( and now we shall do as we have placed the values )
=10x+9+2xy+3yx ANSWER
I hope u have understood by now but if any doubt u can still ask me !
+11912 
