Розділ 3. Одночлени і многочлени » 21 (4-6)

4) 4(4x + 0,5x2) – (2x2 – 5) = 17; 16x + 2x2 – 2x2 + 5 = 17; 16x = 17 – 5; 16x = 12|: 16; x = 0,75. 5) (3x + (–x)2 + 2,8) – (x2 + x3) – 12,2 = 2 – x3; 3x + x2 + 2,8 – x2 – x3 – 12,2 = 2 – x3; 3x = 2 – 2,8 + 12,2; 3x = 11,4|: 3; x = 3,8. 6) (5 + x4 + 6,6x3) – (x4 – x2 – 3x + 8x3 – 2) = 7 + 3x + x2; 5 + x4 + 6,6x3 – x4 + x2 + 3x – 8x3 + 2 = 7 + 3x + x2; –1,4x3 = 7 – 2 – 5; –1,4x3 = 0|: (–1,4) ; x3 = 0; x = 0.