Câu trả lời:

a) 5^x.5=625

=> 5^x+1=5⁴

=> x+1=4=>x=3

b) 3\(\le\)3^x\(\le243\)

=> \(3^1\le3^x\le3^5\)

=> \(1\le x\le5\)=> x=1;2;3;4;5

c) 2^2x-5=32

=> 2^2x-5=2⁵

=> 2x-5=5

=> 2x=10

=> x=5