Question

tìm giá trị của các biểu thức sau

a) \(\dfrac{45^{10}.5^{20}}{75^{15}}\)

b) \(\dfrac{\left(0,8\right)^5}{\left(0,4\right)^6}\)

Answer 1

\(a,\dfrac{45^{10}.5^{20}}{75^{15}}=\dfrac{\left(3^2\right)^{10}.5^{10}.5^{20}}{\left(5^2\right)^{15}.3^{15}}=\dfrac{3^{20}.5^{30}}{5^{30}.3^{15}}=3^5=243\)

\(b,\dfrac{\left(0,8\right)^5}{\left(0,4\right)^6}=\dfrac{\left(0,4.2\right)^5}{\left(0.4\right)^6}=\dfrac{\left(0.4\right)^5.2^5}{\left(0,4\right)^6}=\dfrac{2^5}{0,4}=\dfrac{32}{0,4}=80\)

Answer 2

a,\(\dfrac{45^{10}.5^{20}}{75^{15}}=\dfrac{3^{20}.5^{30}}{3^{15}.3^{30}}=3^5=243\)

b,\(\dfrac{\left(0,8\right)^5}{0,4^6}=\dfrac{0,4^5.2^5}{0,4^6}=\dfrac{2^5}{0,4}=80\)

Answer 3

a/ \(\dfrac{45^{10}.5^{20}}{75^{15}}=\dfrac{\left(5.3^2\right)^{10}.5^{20}}{\left(5^2.3\right)^{15}}=\dfrac{5^{10}.3^{20}.5^{20}}{5^{30}.3^{15}}=\dfrac{5^{30}.3^{20}}{5^{30}.3^{15}}=3^5=243\)

b/ \(\dfrac{\left(0,8\right)^5}{\left(0,4\right)^6}=\dfrac{\left(0,4.2\right)^5}{\left(0,4\right)^6}=\dfrac{\left(0,4\right)^5.2^5}{\left(0,4\right)^6}=\dfrac{2^5}{0,4}=80\)