Please help what is -3/20 x -6

What is the least common multiple of 6 and 17?

Jessica is a custodian at oracle arena.she waxes 20 m2 of the floor in 3/5 of an hour. jessica waxes the floor at a constant rate.at this rate how many sqaures meters can she wax per hour

James adds two numbers a + b. sally adds the same two numbers but reverse the order b + a what property of addition assures us that james and sally will get the same sum