What is 7 divided by c in a algebraic expression

What is 2y+-4y? it's to do with simultaneous equations

Betsy is saving to buy a bird cage. She saves $1 dollar the first week, $3 the second week

In a box of candies the ratio of the number of red to green is 5 : 7 and the ratio of the number of green to blue is 3 : 8. What is the ratio of red to blue?

How many ounces of gold are in aa 1414 -karat gold chain that weighs 2.52.5 ounces?

A box contains 10 transistors, 3 of which are defective. If 3 are selected at random, find the probability of the statements below.

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.