Travis wrote a $53 check for a new pair of shoes. Then, he withdrew $40 from his bank account. What integer represents the change to his bank account balance after the two transactions?

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.