Question

Câu 1.Thực hiện phép tính:

a) -1\(\dfrac{5}{7}.15+\dfrac{2}{7}.\left(-15\right)+\left(-105\right).\left(\dfrac{2}{3}-\dfrac{4}{5}+\dfrac{1}{7}\right)\)

b) \(\dfrac{2^{15}.9^4}{6^6.8^3}\)

Answer 1

a. \(-1\dfrac{5}{7}.15+\dfrac{2}{7}.\left(-15\right)+\left(-105\right).\left(\dfrac{2}{3}-\dfrac{4}{5}+\dfrac{1}{7}\right)\)

\(=\dfrac{-180}{7}+\dfrac{-30}{7}+\left(-105\right).\dfrac{1}{105}\)

\(=\dfrac{-180}{7}+\dfrac{-30}{7}+\left(-1\right)\)

\(=-31\)

b. \(\dfrac{2^{15}.9^4}{6^6.8^3}=\dfrac{2^{15}.\left(3^2\right)^4}{\left(2.3\right)^6.\left(2^3\right)^3}=\dfrac{2^{15}.3^8}{2^6.3^6.2^9}=\dfrac{2^{15}.3^6.3^2}{2^{15}.3^6}=3^2=9\)