Answer:
8 X 10^(9)
Step-by-step explanation:
Originally we have 10 digit phone numbers excluding the area code.
For each face value we have these in store: 0,1,2,3,4,5,6,7,8,9 (total 10)
But if we exclude 1 and 0 for the first digit, we are left with 8 digits.
8P1 X .......
In a phone number, digits can repeat so we can choose out of these 10 numbers freely after this.
8P1 X 10P1 X 10P1 X...
Adding the area code while assuming 10P1 is just 10...we get:
1 X 1 X 1 X 8 X 10^(9)
= 8000000000
Very interesting question, thanks for the opportunity!
A rectangle, presumably, as the cross section is going to be whatever shape the outward faces are (in the case of a vertical cross section like this one)
Step-by-step explanation:
Yes they are equivalent. You get -3 when you try solving the actual equation.
Answer:
The other end point is: s+ti = 3+9i
Step-by-step explanation:
Mid-Point(M) in the complex plane states that the midpoint of the line segment joining two complex numbers a+bi and s+ti is the average of the numbers at the endpoints.
It is given by: 
Given: The midpoint = -1 + i and the segment has an endpoint at -5 - 7i
Find the other endpoints.
Let a + bi = -5 -7i and let other endpoint s + ti (i represents imaginary )
Here, a = -5 and b = -7 to find s and t.
then;
[Apply Mid-point formula]
On comparing both sides
we get;
and 
To solve for s:
or
-2 = -5+s
Add 5 to both side we have;
-2+5 = -5+s+5
Simplify:
3 = s or
s =3
Now, to solve for t;

2 =-7+t
Add 7 to both sides we get;
2+7 = -7+t+7
Simplify:
9 = t
or
t =9
Therefore, the other end point (s+ti) is, 3+9i