Round 8.36 to the nearest one decimal place

What is the perimeter of square abcd? units units 28 units 37 units

Solve for x and y: 217x + 131y = 913; 131x + 217y = 827

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?