Given f(x) = 2x -8 write out in words

Please help this is due today and I really need help.

School has 204 sixth grade students. if the sixth grade is 30% of the total school, how many students are in the middle school?

Expresa commuter train leaves downtown sation and travels at a average speed of 55 miles per hour towards the north side sation, which is 50miles away. thirty minutes later, express commuter train #7 leaves north side and travels at a average speed of 35miles per hour towards downtown sation. at the moment the two trains pass each other, how far(in miles) is train #12 from the downtown sation and how long(in minutes) has the #12 train been traveling

What is the slope of the line shown below?