The negative exponents that are in the numerator pass to positive if the base is moved to the denominator, and the negative exponents that are in the denominator pass to positive if the base is moved to the numerator.
The the answer is the option B: xx^4 / y^2 y^6
By the binomial theorem,

Each term containing a factor 6 is divisible by 3, since 3 divides 6. The remaining 1 and 2 sum to 3, which is also divisible by 3.
Step 1: Insert 2.6 hours for the variable of time and solve.
70.443 + 4.885(2.6)
70.443+ 12.701
= 83.144
This is Ann's EXPECTED exam score. Because of the concert, Ann scored 16 points lower than this number.
Step 2: Subtract 16 from Ann's expected score.
83.144 - 16
= 67.144
For number 3 it would be |-10| and |10|.
Number 5a is supposed to <, because -1 is greater than -7 when you look at the line graph. The same goes for 5b. 5d is >, because 0 is always greater than -1 and it shows that on the line graph that you have there. 5e is =.
I don't see anything else wrong though. Just the ones I listed.
Hope that helps!