Caroline wants to compare the expressions -15-9 and 9 - (- 15) to determine which result is greater. How can she do this without finding the value of each difference? Explain your reasoning.

The party planning committee has to determine the number of tables needed for an upcoming event. if a square table can fit 8 people and a round table can fit 6 people, the equation 150 = 8x + 6y represents the number of each type of table needed for 150 people.