Упр.5.471 ГДЗ Виленкин Жохов 5 класс Часть 2, Просвещение (Математика)

а) (4/9 + 2/9) · 9/13; в) (9/11 — 4/11) · 11/5; д) (2/3)^2 + 13/21 · 7/26 — 5/18;
б) 2/3 · (9/8 — 3/4); г) 2 · 1/8 + 7/12 · 3/7; е) (3/7 — 1/7)^2 · 49/16 + (1/2)^3.

а) $$\left(\frac{4}{9}+\frac{2}{9}\right)\cdot\frac{9}{13}=\frac{6}{9}\cdot\frac{9}{13}=\frac{6}{13}$$

б) $$\frac{2}{3}\cdot\left(\frac{9}{8}-\frac{3}{4}\right)=\frac{2}{3}\cdot\left(\frac{9}{8}-\frac{6}{8}\right)=\frac{2}{3}\cdot\frac{3}{8}=\frac{1}{4}$$

в) $$\left(\frac{9}{11}-\frac{4}{11}\right)\cdot\frac{11}{5}=\frac{5}{11}\cdot\frac{11}{5}=1$$

г) $$2\cdot\frac{1}{8}+\frac{7}{12}\cdot\frac{3}{7}=\frac{2}{8}+\frac{3}{12}=\frac{1}{4}+\frac{1}{4}=\frac{1}{2}$$

д) $$\left(\frac{2}{3}\right)^2+\frac{13}{21}\cdot\frac{7}{26}-\frac{5}{18}=\frac{4}{9}+\frac{1}{6}-\frac{5}{18}$$

$$\frac{4}{9}+\frac{1}{6}-\frac{5}{18}=\frac{8}{18}+\frac{3}{18}-\frac{5}{18}=\frac{6}{18}=\frac{1}{3}$$

е) $$\left(\frac{3}{7}-\frac{1}{7}\right)^2\cdot\frac{49}{16}+\left(\frac{1}{2}\right)^3=\left(\frac{2}{7}\right)^2\cdot\frac{49}{16}+\frac{1}{8}$$

$$\frac{4}{49}\cdot\frac{49}{16}+\frac{1}{8}=\frac{4}{16}+\frac{1}{8}=\frac{1}{4}+\frac{1}{8}=\frac{3}{8}$$

Ответ

а) $$\frac{6}{13}$$; б) $$\frac{1}{4}$$; в) $$1$$; г) $$\frac{1}{2}$$; д) $$\frac{1}{3}$$; е) $$\frac{3}{8}$$.