1) (8а+3b)(3а-8b)-(3a+8b)(8a-3b)== 24a^2 - 64ab + 9b^2 - 24a^2 - 64ab + 9b^2= -128ab + 18b^2
2) (p+3c)c - (3c+p)(c-p) == pc + 3c^2 - (3c^2 - pc - cp + p^2)= pc + 3c^2 - 3c^2 + pc + cp - p^2= 2pc + cp - p^2
1) (8а+3b)(3а-8b)-(3a+8b)(8a-3b)=
= 24a^2 - 64ab + 9b^2 - 24a^2 - 64ab + 9b^2
= -128ab + 18b^2
2) (p+3c)c - (3c+p)(c-p) =
= pc + 3c^2 - (3c^2 - pc - cp + p^2)
= pc + 3c^2 - 3c^2 + pc + cp - p^2
= 2pc + cp - p^2