886. Упростите выражение: a) (0,8x + 15)(0,8x – 15) + 0,36x²; б) 5b² + (3 - 2b)(3 + 2b); в) 2x² – (x + 1)(x – 1); г) (3a – 1)(3a + 1) д) 100x² – (5x-4 e) 22c²+(-3c-7

a) \((0.8x + 15)(0.8x - 15) + 0.36x^2 = 0.64x^2 - 225 + 0.36x^2 = x^2 - 225\) б) \(5b^2 + (3 - 2b)(3 + 2b) = 5b^2 + 9 - 4b^2 = b^2 + 9\) в) \(2x^2 - (x + 1)(x - 1) = 2x^2 - (x^2 - 1) = 2x^2 - x^2 + 1 = x^2 + 1\) г) \((3a - 1)(3a + 1) = 9a^2 - 1\) д) \(100x^2 - (5x - 4)(5x+4) = 100x^2 - (25x^2 -16) = 75x^2 + 16\) e) 22c²+(-3c-7)(3c-7) = 22c^2 + (9c^2 +49)= 31c^2 + 49\) Ответ: a) \(x^2 - 225\) б) \(b^2 + 9\) в) \(x^2 + 1\) г) \(9a^2 - 1\) д) \(75x^2 + 16\) е) \(31c^2 + 49\)