Polygon Q is a scaled copy of polygon P using a scale factor of 1/2 polygon Q's area is what fraction of polygon P's area

I dont understand this, can someone help explain?

Which is an equation for the nth terms of the sequence 12,15,18,21

Darian wants to build a regulation size pool table that is 9 feet in length.he plans he ordered are 18 by 36 inches. what is the scale factor of the dilation he must use to build a regulation pool table

Kayla has a $500 budget for the school party.she paid $150 for the decorations.food will cost $5.50 per student. what inequality represents the number of students,s, that can attend the party?