Розділ 3. Одночлени і многочлени » 14

Знайдіть добуток двочленів: 1) (12 + x)(0,2x – 4) = 2,4x – 48 + 0,2x2 – 4x = 0,2x2 –1,6x – 48. 2) (x + 4,5) • (–x – 2) = –x2 – 2x 4,5x – 9 = x2 – 6,5x – 9; 3) (x2 + x) • (2x + x) = 3x3 + 3x2; 4) (x3 + x2) • (x – 1) = x4 – x3 + x3 – x2 = x4 – x2; 5) (10 + x) • (4x – 1) • (x – 10) = (x2 – 100)(4x – 1) = 4x3 – x2 – 400x + 100; 6) (x2 + 36) • (–x – 6)(–x + 6) = –(x2 + 36)(6 + x) •(6 – x) = –(x2 + 36) • (36 – x2) = (x2 + 36)(x2 – 36) = x4 – 1296; 7) (2 – x)(2x + 1) • (–0,5 + x) = (4x + 2 – 2x2 – x) • (x – 0,5) = (–2x2 + 3x + 2)(x – 0,5) = –2x3 + 3x2 + 2x + x2 – 1,5x – 1 = –2x3 + 4x2 + 0,5x – 1; 8) (x + 4)(x – 4)(x – 5) • (x + 2) = (x2 – 16) • (x2 + 2x – 5x – 10) = (x2 – 16)(x2 – 3x – 10) = x4 – 3x3 – 10x2 – 16x2 + 48x + 160 = x4 – 26x2 + 48x + 160.