Solve this problem

8a-4a (b+4)

Which of the following statements about a variable are true? A variable cannot be subtracted. A variable is represented by a letter. A variable represents a quantity. A variable cannot be multiplied.

Bank A charger a 4$ service fee and $0.25 for each check written. Bank B charges $5 and $0.20 for each check written. How many checks does a person need to write each month for the two banks to charge the same amounts in fees.

10 (7k+9p+3) I don't understand

I rent a gym for $150.00 for 30 students. Another time I rent the gym for $270.00 for 70 students. I need to find a fixed rate. (y = mx+b)

If a stadium has 30,000 seats and tickets are sold at $55 each what percentages of tickets were unsold if the total ticket sales for the game was 1,485,000?

A newspaper reporter wants to know how popular the hobby of bird watching is in the city. He asked people at the local bird refuge if they watched birds as a hobby. Which of the following best explains whether the reporters data is valid or not?

I am very confused on how to figure out if y = 3/4x is proportional?

Alison wants to buy a mountain bike for $339.12. If she saves $28.26 each month, in how many months will she be able to buy the bike?

At 12 o'clock the temperature was 7°C. The temperature decreased by - 20°C. What is the new temperature?

Ashleys rentals charges $27.50 per hour to rent a surfboard and a wetsuit. Darlas surf shop charges $23.25 per hour to rent a surfboard plus $17 extra for a wetsuit.