Find the quotient and the remainder (if any), when:

6x² + x - 15 is divided by 3x + 5.

The area of a rectangle is x³ - 8x² + 7 and one of its sides is x - 1. Find the length of the adjacent side.

(5x - 4y) - (5y - 4x) is equal to:

1. 9(x - y)

2. x - y

3. (y - x)

4. 0