I don't think all of the answer choices are here since they are all the same except for 4. However, the best statement to describe a polygon is that it is a closed plane figure with three or more sides that are straight. The correct answer is A.
D and e would be the answer
The selling price would be $11.20.
40% = 40/100 = 0.4
The mark up is 40% of the cost; this means 40% of 8:
40% of 8 = 0.4(8) = 3.20
8 + 3.20 = 11.20
An expression must contain a variable
The equation y-4=1 has many solution(s).