Question

[Nguyễn Hoàng Nguyên Bảo]

Chứng minh rằng:

a)\(12^8.9^{12}=18^{16}\)

b)\(\frac{\left(5^4-5^3\right)^3}{125^5}=\frac{64}{25^5}\)

c)\(\frac{9^3}{\left(3^4-3^3\right)^2}=\frac{1}{4}\)

Làm nhanh giúp mình nhá. Thanks. ^_^

Answer 1

[Cold Wind]

a) \(VT=12^8\cdot9^{12}=2^{16}\cdot3^8\cdot3^{24}=2^{16}\cdot3^{32}\)

\(VP=18^{16}=2^{16}\cdot3^{32}\)

=> VT=VP

b) \(\frac{\left(5^4-5^3\right)^3}{125^5}=\frac{64}{25^5}\)

(đề sai)

c) \(\frac{9^3}{\left(3^4-3^3\right)^2}=\frac{1}{4}\)

\(VT=\frac{9^3}{\left(3^4-3^3\right)^2}=\frac{3^6}{\left[3^3\left(3-1\right)\right]^2}=\frac{1}{2^2}=\frac{1}{4}=VP\)

Answer 2

[Phạm Minh Anh]

12⁸.9¹²=18⁶

=2¹⁶.3⁸.3²⁴=2¹⁶.3³²

=2¹⁶.3³²=18⁶