I need help with 5,6,7 plz

Astock has a 25% probability of increasing by $10 and a 75% probability of decreasing by $5. what is the stocks expected increase or decrease?

What is the domain of the of the exponential function shown below?

Pranav and molly are selling pies for a school fundraiser. customers can buy blueberry pies and pumpkin pies. pranav sold 6 blueberry pies and 4 pumpkin pies for a total of $106. molly sold 6 blueberry pies and 3 pumpkin pies for a total of $90. find the cost of each of one blueberry pie and one pumpkin pie