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Задача Задача №2692843
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Аноним
28 января 2025 12:07 · публичный вопрос
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Аноним

(2 2/9 +11/12-1 3/4)•7 1/5=7.2

Ответ нейросети
28 января 2025 12:07

Let's break this down step by step to verify the calculation and find the solution.

  1. Convert all mixed numbers to improper fractions:

    • \( 2 \frac{2}{9} = \frac{2 \times 9 + 2}{9} = \frac{18 + 2}{9} = \frac{20}{9} \)
    • \( 1 \frac{3}{4} = \frac{1 \times 4 + 3}{4} = \frac{4 + 3}{4} = \frac{7}{4} \)
    • \( 7 \frac{1}{5} = \frac{7 \times 5 + 1}{5} = \frac{35 + 1}{5} = \frac{36}{5} \)
  2. Rewriting the equation using improper fractions: \[ \left( \frac{20}{9} + \frac{11}{12} - \frac{7}{4} \right) \cdot \frac{36}{5} \]

  3. Finding a common denominator for the fractions in the parentheses:

    • The least common multiple (LCM) of 9, 12, and 4 is 36.
  4. Convert each fraction to have a denominator of 36:

    • \( \frac{20}{9} = \frac{20 \times 4}{9 \times 4} = \frac{80}{36} \)
    • \( \frac{11}{12} = \frac{11 \times 3}{12 \times 3} = \frac{33}{36} \)
    • \( \frac{7}{4} = \frac{7 \times 9}{4 \times 9} = \frac{63}{36} \)
  5. Perform the addition and subtraction: \[ \frac{80}{36} + \frac{33}{36} - \frac{63}{36} = \frac{80 + 33 - 63}{36} = \frac{50}{36} = \frac{25}{18} \]

  6. Now multiply by \( \frac{36}{5} \): \[ \frac{25}{18} \cdot \frac{36}{5} = \frac{25 \cdot 36}{18 \cdot 5} = \frac{900}{90} = 10 \]

The left side evaluates to 10, not 7.2.

Thus, the equation \((2 \frac{2}{9} + \frac{11}{12} - 1 \frac{3}{4}) \cdot 7 \frac{1}{5} = 7.2\) is incorrect. The correct multiplication results in 10.