À study of blood flow involved 27 healthy people aged 18 to 72. Each subject con flow was measured on the first and fifth days of the study. After 5 days, researchers measured what they called "significant improvement" in blood flow and the function of the cells that line the blood vessels. t3 What flaw in the design of this experiment makes it impossi- ble to say if the cocoa really caused the improved blood flow? Explain your answer.

Is trapezoid abdc the result of a dilation of trapezoid mnpq by a scale factor of ? why or why not? yes, because ab and cd are each the lengths mn and qp. yes, because sides ab and cd are parallel to sides mn and qp. no, because ab is the length mn but cd is the length qp. no, because sides ab and cd have different slopes from sides mn and qp.

14. (05.02 lc) what is the value of y in the solution to the following system of equations? (5 points) 2x + y = −4 5x + 3y = −6

Martha has a deck of cards. she has lost some of the cards, and now the deck only contains nine spades, eleven diamonds, eight clubs, and twelve hearts. martha predicts that whenever she draws a card from the deck without looking, she will draw a club one-fifth of the time. which activity would best allow martha to test her prediction? a. randomly draw a card from the box and see if it is a club. b. randomly draw a card. then, continue to draw another card until all eight clubs are drawn. c. randomly draw and replace a card 120 times. then, observe how close to 30 times a club is drawn. d. randomly draw and replace a card 100 times. then, observe how close to 20 times a club is drawn.