All irrational numbers are real numbers. ☺
Answer: D. 7^11
Reason:
The rule we use is 
When multiplying exponentials of the same base, we add the exponents.
The exponents 5 and 6 add to 5+6 = 11
So,

The base stays the same the entire time.
This system equation is not solution
Answer:
-20 < 4 - 2x (subtract 4 from both sides)
-24 < -2x (divide each side by -2)
12> x (when you divide by a negative number, the inequality flips)
x< 12 ( I always put it so x is first)
so the answer is C
Answer:
-8.5 is a rational number
Step-by-step explanation:
The whole numbers are all the numbers you can reach if you start at 1 (or 0, if that's your thing) and count forward - 1, 2, 3, 4, on and on forever. The integers are all the numbers we can get by adding and subtracting two whole numbers - this includes situations like 3 - 4, where we're "taking away" more than we have: we simply invent numbers less than zero, the negatives, and that gives 3 - 4 a value - the number -1.
So we can add, subtract and multiply any of these numbers together and we end up somewhere else our world of integers, but the moment we want to ask a question like "what numbers are between 0 and 1?" the integers just aren't enough. We need fractions, and for that purpose we create the rational numbers, which include all the fractional parts between integers, as well as the integers themselves.
-8.5 is halfway between the integers -8 and -9, and since it has a fractional part, it must be a rational number.