Question

Мне нужно помощь по математике

Answer 1

$5.$

$2 - 3 \frac{1}{7} \times (2 - 1 \frac{9}{11} ) \div \frac{8}{21} = 2 - \frac{22}{7} \times (1 \frac{11}{11} - 1 \frac{9}{11} ) \times \frac{21}{8} = 2 - \frac{22}{7} \times \frac{2}{11} \times \frac{21}{8} = 2 - \frac{3}{2} = 2 - 1 \frac{1}{2} = 1 \frac{2}{2} - 1 \frac{1}{2} = \frac{1}{2} = 0.5$

$6. \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \\ (1.75 + x) \div 1.9 = 12 - 9.5 \\ 1.75 + x = 22.8 - 18.05 \\ 1.75 + x = 4.75 \\ x = 4.75 - 1.75 \\ x = 3$

Answer 2

Пошаговое объяснение:

№5

1) 2 - 1 9/11 = 1 11/11 - 1 9/11 = 2/11

2) 3 1/7 * 2/11 = 22/7 * 2/11 = 2/7 * 2/1 = 4/7

3) 4/7 : 8/21 = 4/7 * 21/8 = 1/1 * 3/2 = 3/2 = 1 1/2

4) 2 - 1 1/2 = 1 2/2 - 1 1/2 = 1/2

№6

(1,75 + х) : 1,9 = 12 - 9,5

(1,75 + х) : 1,9 = 2,5

1,75 + х = 2,5 * 1,9

1,75 + х = 4,75

х = 4,75 - 1,75

х = 3