What’s the slope and y intercept of y=-2x+7

The parabola x= √y-9 opens: a.)up b.)down c.)right d.)left

Write the fraction or mixed number and the decimal shown by the model

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?