Answer:
-8i
Step-by-step explanation:
To multiply numbers is polar form
z1 = r1 ( cos theta 1 + i sin theta 1)
z2 = r2 ( cos theta 2 + i sin theta 2)
z1*z2 = r1*r2 (cos (theta1+theta2) + i sin (theta1+theta2)
z1 = 2(cos 70° + i sin 70°)
z2 = 4(cos 200+ i sin 200)
z1z2 = 2*4 (cos (70+200) + i sin (70+200)
z1z2 = 8 (cos(270) + i sin (270))
= 8 (0 + i (-1))
=-8i
Answer:
The required equation is
.
Step-by-step explanation:
If a quadratic equation is
, then the quadratic formula is

The given quadratic equation is

Here, a=1, b=-9 and c=-20.
Substitute a=1, b=-9 and c=-20 in the above quadratic formula.

Therefore the required equation is
.
Answer:
<h3>

</h3>
Step-by-step explanation:
<h3>to understand this</h3><h3>you need to know about:</h3>
- inequality
- solving inequality
- PEMDAS
<h3>given:</h3>
5 ≤ - 3x- 3 ≤ 10
<h3>to solve:</h3>
x
<h3>let's solve:</h3>
few notes about inequality
the direction of the inequality doesn't change if you
- Add (or subtract) a number from both sides
- Multiply (or divide) both sides by a positive number
- Simplify a side
the direction of the inequality does change
if you
- Multiply (or divide) both sides by a negative number
- Swapping left and right hand sides







Answer:
217945728000 ways
Step-by-step explanation:
Given
--- 1 dozen

The given condition implies that;
---- any of the 4 shelves
--- any of the 4 shelves and either ways of book 1
--- any of the 4 shelves and either ways of book 1 and 2
-----------------------
----------------
----------
<h2>

</h2><h2>
</h2>
So, the number of ways is:


Answer:
The age of the person who entered the room is 15
Step-by-step explanation:
Ages of 5 people in a room are:
17, 16, 15, 17, 22
A person enters room, the mean age of 6 people is 17.
We need to find the age of person who entered the room.
We know that: 
Now, we have mean of 6 people that is 17
We know the age of 5 people while age of one person is unknown.
Let age of person which is unknown= x
So, we can write:
Sum of all data values = 17+16+ 15+ 17+ 22+x
where x is the age of person who enters the room.
Finding x

So, we get the value of x: x=15
Therefore, the age of the person who entered the room is 15.