a) `2^x : 2 = 16`
`=> 2^(x-1) =16`
`=> 2^(x-1) = 2^4`
`=> x -1 =4`
`=> x = 4+1`
`=> x=5`
Vậy `x =5`
b) `(2x-4)^3 = (2x-4)^2`
`=> (2x-4)^3 - (2x-4)^2 =0`
`=> (2x-4)^2 ( 2x-4 - 1) =0`
`=> (2x-4)^2 ( 2x -5)=0`
+) `(2x-4)^2 =0`
`=> 2x-4=0`
`=> 2x =4`
`=> x=2`
+) `2x-5=0`
`=> 2x =5`
`=> x= 5/2`
Vậy `x= 2` hoặc `x= 5/2`
c) `(x-2)^4 = (x-2)^3`
`=> (x-2)^4 - (x-2)^3 =0`
`=> (x-2)^3 ( x-2 -1) =0`
`=> (x-2)^3 (x -3)=0`
+) `(x-2)^3 =0`
`=> x-2=0`
`=> x=2`
+) `x-3=0`
`=> x= 3`
Vậy `x=2` hoặc `x= 3`
d) `(3x-9)^5 = (3x-9)^6`
`=> (3x-9)^6 - (3x -9)^5=0`
`=> (3x-9)^5 ( 3x -9 -1) =0`
`=> (3x-9)^5 . ( 3x -10)=0`
+) `(3x-9)^5 =0`
`=> 3x -9 =0`
`=> 3x = 9`
`=> x= 3`
+) `3x-10 =0`
`=> 3x= 10`
`=> x= 10/3`
Vậy `x= 3` hoặc `x= 10/3`
e) `2^(3x) . 2^x = 64`
`=> 2^ (3x+x) =64`
`=> 2^(4x) =64`
`=> 2^(4x) = 2^6`
`=>4x=6`
`=> x= 3/2`
Vậy `x = 3/2`
