In Mei Lin's school, her science teacher gives tests that are marked out of 100. Mei Lin has an average of 60 marks on her first four Science tests. On the fifth test she got 80 marks. What is the average of Mei Lin's marks in Science after all five tests? Please help ASAP

What is the y intercept of f(x)=(1/2)^x?

Can someone me do math because i am having a breakdown rn because i don’t get it

The first side of a triangle measures 5 in less than the second side, the third side is 3 in more than the first side, and the perimeter is 17 in. how long is the third side? if s represents the length of the second side, which of the following represents the length of the third side? s-5 ws-2 s+ 3 next question ask for turn it in