Question

tìm  x 

a , \(5^x.\left(5^3\right)^2=625\)

b , \(172.x^2-7^9:98=2^{-3}\)

Answer 1

Ta có ; \(5^x.\left(5^3\right)^2=625\)

\(\Leftrightarrow5^x.5^6=625\)

\(\Leftrightarrow5^{x+6}=5^4\)

<=> x + 6 = 4

<=> x = -2 

Answer 2

a,ta có

\(5^x\left(5^3\right)^2=625\)

\(5^x.5^6=5^4\)

\(5^{x+6}=5^4\)

\(x+6=4\)

\(x=-2\)

b, đề sai hay sao đó x=48,9287366