Use the properties of operations and rules to solve a multi-step mathematical problem

Use the properties of operations and rules for multiplying and dividing signed numbers to solve:
(-4)×(7/5)×(-3/4)÷(7/15)
Answer: 9

1 answer

To solve the expression \((-4) \times \left(\frac{7}{5}\right) \times \left(-\frac{3}{4}\right) \div \left(\frac{7}{15}\right)\), we will follow the order of operations and apply the properties of signed numbers.

  1. Rearranging and simplifying the division: Dividing by a fraction is the same as multiplying by its reciprocal. Therefore, we can rewrite the expression as: \[ (-4) \times \left(\frac{7}{5}\right) \times \left(-\frac{3}{4}\right) \times \left(\frac{15}{7}\right) \]

  2. Grouping the factors: We can rearrange the order of multiplication: \[ (-4) \times \left(-\frac{3}{4}\right) \times \left(\frac{7}{5}\right) \times \left(\frac{15}{7}\right) \]

  3. Multiplying the signed numbers: First, we can compute \((-4) \times \left(-\frac{3}{4}\right)\): \[ (-4) \times \left(-\frac{3}{4}\right) = 4 \times \frac{3}{4} = 3 \]

  4. Now, substitute this back into the expression: Our expression now simplifies to: \[ 3 \times \left(\frac{7}{5}\right) \times \left(\frac{15}{7}\right) \]

  5. Simplifying further: Notice that \(\frac{7}{5} \times \frac{15}{7}\): \[ \frac{7}{5} \times \frac{15}{7} = \frac{15}{5} = 3 \]

  6. Final multiplication: Now, we multiply the result by 3: \[ 3 \times 3 = 9 \]

Thus, the final answer is: \[ \boxed{9} \]