Question

Tìm x biết:

1) 9^x-1=9

2) 27: 3^x=3

3) \(\frac{1}{9}\). 3⁴.3^x=3⁷

Answer 1

\(9^{x-1}=9\)

\(x-1=1\)

\(x=2\)

Answer 2

\(27:3^x=3\)

\(3^x=9\)

\(3^x=3^2\)

x=2

Answer 3

\(\frac{1}{9}.3^4.3^x=3^7\)

\(3^x=3^5\)

\(x=5\)

Answer 4

1) \(9^{x-1}=9\) 

\(\Rightarrow x-1=1\) 

\(x=1+1\) 

\(x=2\) 

Vậy \(x=2\) 

2) \(27\div3^x=3\) 

\(3^x=27\div3\) 

\(3^x=9\) 

\(\Rightarrow3^x=3^2\)

\(\Rightarrow x=2\) 

Vậy \(x=2\) 

3) \(\frac{1}{9}.3^4.3^x=3^7\)

\(9.3^x=3^7\)

\(\Rightarrow3^2.3^x=3^7\)

\(3^x=3^7\div3^2\) 

\(3^x=3^{7-2}\)

\(3^x=3^5\)

\(\Rightarrow x=5\)

Vậy \(x=5\)

 

Answer 5

27:3^X=3=>3^X=9=>X=2

TICK CHO MIK NHA