Which function models the price of a new dvd x years after 2013

Match the equivalent expressions. x - 3y + 12 12 - 3y - 2x + x + 2x 3x + 2y - 2x + y + 12 3y + 12 3x + y - 12 4y + 3y + 3x - 6y - 10 - 2 x + 3y + 2x - 3x + 7 + 5 x + 3y + 12 5 + 2y + 7x - 4x + 3y - 17

The base of a triangle exceeds the height by 7 centimeters. if the area is 400 square centimeters, find the length of the base and the height of the triangle.

What numbers are included in the set of integers? what numbers are not included?