б) A = a²+za³-²; B=ZQ²-za²+a². Найти: А-В

б) $$A = \frac{2}{3}a^4 + \frac{3}{4}a^3 - \frac{1}{3}a^2; B = \frac{1}{6}a^4 - \frac{1}{8}a^3 + \frac{1}{3}a^2$$. Найти: A-B

$$A - B = (\frac{2}{3}a^4 + \frac{3}{4}a^3 - \frac{1}{3}a^2) - (\frac{1}{6}a^4 - \frac{1}{8}a^3 + \frac{1}{3}a^2) = \frac{2}{3}a^4 + \frac{3}{4}a^3 - \frac{1}{3}a^2 - \frac{1}{6}a^4 + \frac{1}{8}a^3 - \frac{1}{3}a^2 = (\frac{2}{3}a^4 - \frac{1}{6}a^4) + (\frac{3}{4}a^3 + \frac{1}{8}a^3) + (-\frac{1}{3}a^2 - \frac{1}{3}a^2) = (\frac{4}{6}a^4 - \frac{1}{6}a^4) + (\frac{6}{8}a^3 + \frac{1}{8}a^3) + (-\frac{1}{3}a^2 - \frac{1}{3}a^2) = \frac{3}{6}a^4 + \frac{7}{8}a^3 - \frac{2}{3}a^2 = \frac{1}{2}a^4 + \frac{7}{8}a^3 - \frac{2}{3}a^2$$

Ответ: $$\frac{1}{2}a^4 + \frac{7}{8}a^3 - \frac{2}{3}a^2$$