Question

[mai thuy phuong]

1.Tìm x

a)(1/4) mũ x :1/16=1/4

b)81 mũ x:9 mũ x=729

giúp mk nha!Thanks nhìu

Answer 1

[๖ۣۜFunny-Ngốkツ]

a) \(\left(\frac{1}{4}\right)^x:\frac{1}{16}=\frac{1}{4}\)

\(\left(\frac{1}{4}\right)^x=\frac{1}{4}\cdot\frac{1}{16}\)

\(\left(\frac{1}{4}\right)^x=\frac{1}{64}\)

\(\left(\frac{1}{4}\right)^x=\left(\frac{1}{4}\right)^3\)

\(\Rightarrow x=3\)

b) \(81^x:9^x=729\)

\(\left(81:9\right)^x=729\)

\(9^x=9^3\)

\(\Rightarrow x=3\)

Answer 2

[Nguyễn Thanh Hiền]

a) \(\left(\frac{1}{4}\right)^x:\frac{1}{16}=\frac{1}{4}\)

\(\Rightarrow\left(\frac{1}{4}\right)^x=\frac{1}{4}\times\frac{1}{16}\)

\(\Rightarrow\left(\frac{1}{4}\right)^x=\frac{1}{64}\)

\(\Rightarrow\left(\frac{1}{4}\right)^x=\left(\frac{1}{4}\right)^3\)

\(\Rightarrow x=3\)

Vậy x = 3

b) \(81^x:9^x=729\)

\(\Rightarrow\left(81:9\right)^x=729\)

\(\Rightarrow9^x=9^3\)

\(\Rightarrow x=3\)

Vậy x = 3

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