Question

c) 2 . 5^x-2 + 3 . 5^x-2= 625

Giúp mình với làm ơn đi

Answer 1

\(2.5^{x-2}+3.5^{x-2}=625\)

\(5^{x-2}\left(2+3\right)=625\)

\(5^{x-2}=625\div5\)

\(5^{x-2}=125\)

\(5^{x-2}=5^3\)

\(\Rightarrow x-2=3\Leftrightarrow x=5\)

Answer 2

\(2\cdot5^{x-2}+3\cdot5^{x-2}=625\)

\(\Rightarrow5^{x-2}\cdot\left(2+3\right)=625\)

\(\Rightarrow5^{x-2}\cdot5=625\)

\(\Rightarrow5^{x-2}=625:5=125\)

\(\Rightarrow5^x:5^2=125\)

\(\Rightarrow5^x=125\cdot25=3125\)

\(\Rightarrow5^x=5^5\)

\(\Rightarrow x=5\)

Answer 3

2.5^x-2+5^x-2=625

5^x-2.(2+3)=625

5^x-2.5=625

5^x-2=625:5

5^x-2=125

5^x-2=5³

=>x-2=3

x=3+2

x=5