Question

Tìm giá trị biểu thức:

a) A=\(\dfrac{45^3.20^4.18^2}{180^5}\)

b) B=\(\dfrac{11.3^{22}.3^7-9^{15}}{\left(2.3^{14}\right)^2}\)

Answer 1

45³ = (9.5)³ = 3⁶.5³

20⁴ = (4.5)⁴ = 2⁸.5⁴

18² = (9.2)² = 3⁴.2²

180⁵ = (4.9.5)⁵ = 2¹⁰.3¹⁰.5⁵

\(=\dfrac{3^6.5^3.2^8.5^4.3^4.2^2}{2^{10}.3^{10}.5^5}=\dfrac{2^{10}.3^{10}.5^7}{2^{10}.3^{10}.5^5}=5^2=25\)

Answer 2

\(B=\dfrac{11.3^{29}-3^{30}}{4.3^{28}}=\dfrac{3^{29}\left(11-3\right)}{3^{28}.4}=\dfrac{3.8}{4}=6\)