Объяснение:
1. (b-9)^2 = b^2-2×b×9+9^2 = b^2-18b+81
2. (7+6a)^2 = 7^2+2×7×6a+(6a^2) = 49+84a+36a^2
3. (4c-y)(4c+y) = (4c)^2-y^2
4. 3p^2-12p-p^2+2^2 = 2p^2-12p+4
5. c^2-2×c×3+3^2-2c^2+4c = -c^2-2c+9
6. 10py+5(p^2-2×p×y+y^2)=10py+5p^2-10py+5y^2=5p^2+5y^2