The correct answer is (-12)^15, because you have to multiply the exponents.

44 because 4 times 1 is 4 and 6 times 4 is 24 so in the answer would be 2240
It looks like the practice ones are all that matter so I'm only going to answer those. If you need the others answered let me know.
1. 5k-9=-3k+7
Add 9 to both sides: 5k-9+9=-3k+7+9
5k=-3k+16
Add 3k to both sides: 5k+3k=-3k+16+3k
(You are adding 3 and 9 instead of subtracting them because in the equation, they are negative numbers and you have to do the opposite operation to get rid of them.)
8k=16
Divide both sides by 8: 8k/8=16/8
k=2
2. 2(w-3)+5=3w-2
Use the distributive property: 2*w-2*3+5=3w-2
2w-6+5=3w-2
Combine like terms: 2w-1=3w-2
Add 1 to both sides: 2w-1+1=3w-2+1
2w=3w-1
Subtract 3w from both sides: 2w-3w=3w-1-3w
-w=-1
Divide both sides by -1: -w/-1=-1/-1
w=1
3. 8t+9=7t+6
Subtract 9 from both sides: 8t+9-9=7t+6-9
8t=7t-3
Subtract 7t from both sides: 8t-7t=7t-3-7t
t=-3