x(y - z) + y(z - x) - z(y - x) is equal to:

1. 0

2. xy + yz + zx

3. xy + yz - zx

4. xy - yz + zx

Simplify:

a² - 2a + {5a² - (3a - 4a²)}

Simplify:

-3(1 - x²) - 2{x² - (3 - 2x²)}