A) (c-9)(c+9)-(c+4)(c-4)= c^2 - 81 - c^2 + 4c + 4c - 16= 8c - 97
Б) (7c+2)(7c-2)-(7c-5)(7c+5)= 49c^2 - 4 - 49c^2 - 25= -29
В) (3c+1)(1-3c)+(3c-8)(8+3c)= 3c - 9c^2 + 1 - 3c + 24c - 8 + 24c^2 - 64= 21c^2 + 24c - 71
Г) (0.3c+1.1)(1.1-0.3c)+(0.3c-0.2)(0.2+0.3c)= 0.03c - 0.33c^2 + 1.1 - 0.33c + 0.24c - 0.2 + 0.03c^2 - 0.06= -0.3c^2 + 0.06c + 0.84
A) (c-9)(c+9)-(c+4)(c-4)
= c^2 - 81 - c^2 + 4c + 4c - 16
= 8c - 97
Б) (7c+2)(7c-2)-(7c-5)(7c+5)
= 49c^2 - 4 - 49c^2 - 25
= -29
В) (3c+1)(1-3c)+(3c-8)(8+3c)
= 3c - 9c^2 + 1 - 3c + 24c - 8 + 24c^2 - 64
= 21c^2 + 24c - 71
Г) (0.3c+1.1)(1.1-0.3c)+(0.3c-0.2)(0.2+0.3c)
= 0.03c - 0.33c^2 + 1.1 - 0.33c + 0.24c - 0.2 + 0.03c^2 - 0.06
= -0.3c^2 + 0.06c + 0.84