Keywords:
<em>System of equations, variables, hardcover version, paperback version, books
</em>
For this case we must construct a system of two equations with two variables. Let "h" be the number of hardcover version books, and let "p" be the number of paperback version books. If the hardcover version of a book weighs 7 ounces and the paperback version weighs 5 ounces, to reach a total of 249 ounces we have:
(1)
On the other hand, if there are Forty-five copies of the book then:
(2)
If from (2) we clear the number of books paperback version we have:

As each paperback version book weighs 5 ounces, to obtain the total weight of the paperback version books, represented by "x" in the table shown, we multiply
So, 
Answer:

Option D
X is 5. Hope this helps:)
Answer: 2√2 - 3Explanation:The expession written properly is:

To rationalize that kind of expressions, this is to eliminate the radicals on the denominator you use conjugate rationalization.
That is, you have to multiply both numerator and denominator times the conjugate of the denominator.
The conjugate of √3+√6 is √3 - √6, so let's do it:

To help you with the solution of that expression, I will show each part.
1) Numerator: (√3 - √6) . (√3 - √6) = (√3 - √6)^2 = (√3)^2 - 2√3√6 + (√6)^2 =
= 3 - 2√18 + 6 = 9 - 6√2.
2) Denominator: (√3 + √6).(√3 - √6) = (√3)^2 - (√6)^2 = 3 - 6 = - 3
3) Then the resulting expression is:
9 - 6√2
-----------
-3
Which can be further simplified, dividing by - 3
-3 + 2√2
Answer: 2√2 - 3
The first answer is B: 2 1/2
4 5/6 is put there twice except the last one is subtracting so you can put, 4 5/6 - 4 5/6 = 0 therefore the only number left is 2 1/2
the second one I really don't know sorry:(
The third answer is C because the cases come in 24. But they didn't tell you how many case she brought so the variable has to be by 24 and they took 43 which is the subtracting factor. So the answer is C.
And I also don't know the last one again sorry:(