Реши уравнения:
а)

\frac{x}{14} = 30

;

\frac{80}{y} = 5

;

\frac{m}{28} = 36

;

\frac{513}{n} = 19

.
б)

(a + 3 \frac{4}{7}) - 1 \frac{2}{7} = 4 \frac{3}{7}

2 \frac{19}{23} - (\frac{5}{23} + b) = 1 \frac{6}{23}

(c - 2 \frac{3}{11}) + 5 \frac{1}{11} = 7

3 \frac{4}{9} + (8 - d) = 6 \frac{5}{9}

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ГДЗ учебник по математике 4 класс Петерсон. 17 урок. Шкалы. Номер №8

\frac{x}{14} = 30

x : 14 = 30
x = 30 * 14
x = 420

\frac{80}{y} = 5

80 : y = 5
y = 80 : 5
y = 16

\frac{m}{28} = 36

m : 28 = 36
m = 36 * 28
m = 1008

\frac{513}{n} = 19

513 : n = 19
n = 513 : 19
n = 27

(a + 3 \frac{4}{7}) - 1 \frac{2}{7} = 4 \frac{3}{7}

a + 3 \frac{4}{7} = 4 \frac{3}{7} + 1 \frac{2}{7}

a + 3 \frac{4}{7} = 5 \frac{5}{7}

a = 5 \frac{5}{7} - 3 \frac{4}{7}

a = 2 \frac{1}{7}

2 \frac{19}{23} - (\frac{5}{23} + b) = 1 \frac{6}{23}

\frac{5}{23} + b = 2 \frac{19}{23} - 1 \frac{6}{23}

\frac{5}{23} + b = 1 \frac{13}{23}

b = 1 \frac{13}{23} - \frac{5}{23}

b = 1 \frac{8}{23}

(c - 2 \frac{3}{11}) + 5 \frac{1}{11} = 7

c - 2 \frac{3}{11} = 7 - 5 \frac{1}{11}

c - 2 \frac{3}{11} = 6 \frac{11}{11} - 5 \frac{1}{11}

c - 2 \frac{3}{11} = 1 \frac{10}{11}

c = 1 \frac{10}{11} + 2 \frac{3}{11}

c = 3 \frac{13}{11}

c = 4 \frac{2}{11}

3 \frac{4}{9} + (8 - d) = 6 \frac{5}{9}

8 - d = 6 \frac{5}{9} - 3 \frac{4}{9}

8 - d = 3 \frac{1}{9}

d = 8 - 3 \frac{1}{9}

d = 7 \frac{9}{9} - 3 \frac{1}{9}

d = 4 \frac{8}{9}

ГДЗ Математика 4 класс Петерсон