Question

Tìm x

5^x x 5^x+1 x 5^x+2  = 10²¹ : 2²¹

 

Answer 1

\(5^x\times5^{x+1}\times5^{x+2}=10^{21}:2^{21}\)

\(5^{3\times x+3}=5^{21}\)

\(3\times x=21-3=18\)

\(\Rightarrow x=18:3=6\)

Answer 2

\(5^x\cdot5^{x+1}\cdot5^{x+2}=10^{21}:2^{21}\)

\(5^{3x+3}=5^{21}\)

\(3x+3=21\)

\(x+1=7\)

\(x=6\)