n(A-B) denotes elements which are in A but not in B
n(Au B) denotes elements in A and B
n(AnB) denotes elements that are common in A and B
Now I will add one more set
n(B-A) which denotes elements in B but not in A
So, n(AuB) = n(A-B) + n( B-A) +n(AnB)
70 = 18 +n(B-A) + 25
70 = 43 + n(B-A)
n(B-A) = 70-43
n(B-A) = 27
So, n(B) = n( B-A) + n( AnB)
= 27+25
= 52
Answers:

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Explanation:

Note we subtract 3 off the previous term (t1) to get the next term (t2). Each new successive term is found this way

and so on. This process may take a while to reach 
There's a shortcut. The nth term of any arithmetic sequence is

We plug in
and simplify

Then we can plug in various positive whole numbers for n to find the corresponding
value. For example, plug in n = 2

which matches with the second term we found earlier. And,

---------------------
The notation
refers to the sum of the first ten terms 
We could use either the long way or the shortcut above to find all
through
. Then add those values up. Or we can take this shortcut below.

The sum of the first ten terms is -85
-----------------------
As a check for
, here are the first ten terms:
- t1 = 5
- t2 = 2
- t3 = -1
- t4 = -4
- t5 = -7
- t6 = -10
- t7 = -13
- t8 = -16
- t9 = -19
- t10 = -22
Then adding said terms gets us...
5 + 2 + (-1) + (-4) + (-7) + (-10) + (-13) + (-16) + (-19) + (-22) = -85
This confirms that
is correct.
Answer:
The First Graph -2○ and 4○
Step-by-step explanation:
Because these numbers aren't included in the solution.
First evaluate 990 x 37.
990 x 37 = 36630
Test the given numbers to find the pair that adds up to 36630.
Test 297.
The missing pair will be
36630 - 297 = 36333
Will not work
Test 693.
36630 - 693 = 35937
Will not work
Test 2970.
36630 - 2970 = 33660
Will not work
Test 6930
36630 - 6930 = 29700
This works, because 6930 + 29700 = 36630.
Answer: 6930 and 29700.
Answer:3.1875
Step-by-step explanation: Simplifying
-3 + 8 + -8(7 + -2a) = 0
-3 + 8 + (7 * -8 + -2a * -8) = 0
-3 + 8 + (-56 + 16a) = 0
Combine like terms: -3 + 8 = 5
5 + -56 + 16a = 0
Combine like terms: 5 + -56 = -51
-51 + 16a = 0
Solving
-51 + 16a = 0
Solving for variable 'a'.
Move all terms containing a to the left, all other terms to the right.
Add '51' to each side of the equation.
-51 + 51 + 16a = 0 + 51
Combine like terms: -51 + 51 = 0
0 + 16a = 0 + 51
16a = 0 + 51
Combine like terms: 0 + 51 = 51
16a = 51
Divide each side by '16'.
a = 3.1875
Simplifying
a = 3.1875