§ 3. МНОГОЧЛЕНИ » 255

255. а) 7х4 – (4x2 – x4 + 3x) – (–3x2 + 8x4 + 2x); б) 6ab + 3b2 – (1 + 2b2) – (–2ab – 3b2) + 1; в) 2n2 + 3n – (–3n – 1 + 2n2 – (n – 1 – n2)).