What is a rule for the sign of a product of more than 2 negative integers

Agiven line has the equation 2x + 12y = −1. what is the equation, in slope-intercept form, of the line that is perpendicular to the given line and passes through the point (0, 9)? y = ( )x + 9

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.

He ! a group of farmers planned to clean 80 acres of wheat per day to finish the work on schedule. right before the work started, they received a new piece of machinery that them clean 10 more acres per day than originally planned. as a result of increased productivity in the last day before the deadline they only had to clean 30 acres. how many acres of wheat did the group of farmers have to clean?