Помогите пожалуйста,обведённые номераplease help

Ответ

Автор - maymr

Здравствуйте!

1)
$frac{1}{24} x - ( frac{1}{3} x + ( - frac{2}{9} x - ( - frac{4}{9} x + ( - frac{5}{12} x)))) = \ \ = frac{1}{24} x - ( frac{1}{3} x + ( - frac{2}{9} x - ( - frac{16}{36} x - frac{15}{36} x))) = \ \ = frac{1}{24} x - ( frac{1}{3} x + ( - frac{8}{36} x + frac{31}{36} x)) = \ \ frac{1}{24} x - ( frac{12}{36} x + frac{23}{36} x) = \ \ = frac{1}{24} x - frac{35}{36} x = \ \ = frac{3}{72} x - frac{70}{72} x = \ \ = - frac{67}{72} x$

2)
$8.4 - 2.7(7b - 1.3(10 - 11b)) - 15.7b = \ = 8.4 - 2.7(7b - 13 + 14.3b) - 15.7b = \ = 8.4 - 18.9b + 35.1 - 38.61b - 15.7b = \ = 43.5 - 73.21b$
3)
$- frac{3}{40} ( - 2a - ( frac{1}{3} + 12y)) - frac{1}{7} ( - 14a - (7 + frac{2}{3} a)) = \ \ = - frac{3}{40} ( - 2a - frac{1}{3} - 12y) - frac{1}{7} ( - 14a - 7 - frac{2}{3} a) = \ \ = frac{3}{20} a + frac{1}{40} + 0.9y + 2a + 1 + frac{2}{21} a= \ \ = 2 frac{103}{420} a + 1.025 + 0.9y$

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