Simplify the variable expression by evaluating it's numerical part m-8+143-5 and how did get m

What is 20+(5 x 2/5 )+ 3 show your work

10 ! a train starts from grand city and travels toward belleville 388 miles away. at the same time, a train starts from belleville and runs at the rate of 47 miles per hour toward grand city. they pass each other 4 hours later. find the rate of the train from grand city.

What are the exclude value of mn+3m