Упрости выражения.
1. 8–(y+4)(y–4).
2. (3b+5c)(5c–3b) + 9b^2
3. 9x(2–x)+(3x+2)^2.
4. 4(x^2+4)–(5x–4)^2.
5. 3(x+y)^2–6xy.
6. (x–3)^2–(x+3)(3–x).