4 deg . Спростіть вираз: 1) (x - 4)(x + 4) - x(x - 5) 2) (c + 3) ^ 2 + (c - 7)(c + 1)

1) (x - 4)(x + 4) - x(x - 5)
= x^2 + 4x - 4x - 16 - x^2 + 5x
= 4x - 16 + 5x
= 9x - 16

2) (c + 3) ^ 2 + (c - 7)(c + 1)
= c^2 + 6c + 9 + c^2 - 7c + c - 7
= 2c^2 - 6c + 2