Help with exponential equations? Just five--I don't get it >.<

I don't often resort to yahoo! answers for homework help, but damn this is confusing.
1. Solve 7^(x-5)=7^(4x+7)

2. Solve 3^(x-5)=9

3. Solve 81^x=27^(x+2)

4. Solve (1/36)=6^(x-3)

5. Solve (sqrt:6)^(8x)=216^(x-3)

ANY help is appreciated, thanks.
\m/

1.
7^(x-5)=7^(4x+7)
x - 5 = 4x + 7
x = -12/3 = -4

2.
3^(x-5)=9
3^(x-5)=3^2
x-5 = 2
x = 7


3.
81^x=27^(x+2)
3^4x = 3^3(x+2)
4x = 3(x+2)
x = 6

4.
(1/36)=6^(x-3)
6^(-2) = 6^(x-3)
-2 = x-3
x = 1

5.
(sqrt:6)^(8x)=216^(x-3)
6^(1/2)(8x) = 6^6(x-3)
(1/2)(8x) = 6(x-3)
4x = 6x-18
-2x = -18
x = 18/2 = 9

Sometime we feel tired, so others help us! Be happy friend ;-)

sry