Start with

Add 2x to both sides:

Subtract 21 from both sides:

Divide both sides by 5. Since it is positive, we don't have to change the inequality sign:

So, the answer is 
Answer:
-56
Step-by-step explanation:
Formula to get determinant is::
![\left[\begin{array}{ccc}a&b\\c&d\end{array}\right] = ad-bc](https://tex.z-dn.net/?f=%5Cleft%5B%5Cbegin%7Barray%7D%7Bccc%7Da%26b%5C%5Cc%26d%5Cend%7Barray%7D%5Cright%5D%20%3D%20ad-bc)
0(0)-8(7)
0 - 56
-56
Step-by-step explanation:
to find a common denominator, you have to find a number that "works" with every other number.
for example, say you have
2/4 and 8/12
First you need to find the common factor between 4 and 12, so list all your fours
4, 8, 12, 16, 20
Now list all your twelves
12, 24, 36, 48, 60
to find the common factor you look at both your list of numbers and find one that's the same, sometimes it takes a long list of numbers to find the common factor, but you will run into one.
So by looking at our list we see that 4 and 12 share the common factor of 12. but since 8/12 already has a denominator of 12, we are going to leave it alone.
now think about what you would multiply 4 by, to get to 12. The answer is
4 x 3 = 12
to make the numerator correct, you multiply it by the same number you did 4, so since your faction is 2/4 you should do 2 x 3 = 6
now you have your answer,
2/4 and 8/12 turns into
6/12 and 8/12
and that's how you find it, let me know if you have questions :)
Answer:
Suppose that A is the set of sophomores at your school and B is the set of students in discrete mathematics at your school.
a) It is the intersection A ∩ B
b) This is the difference A − B.
c) It is the union A ∪ B.
--- ---
d) It can be shown as A ∪ B. (bar over A and B both)
The estimated portion of light bulbs that last more than 500 hours will be
x=∑xn=224/430=0.521=52.1%