Answer:
See proof below
Step-by-step explanation:
Let
. If w=-z, then r=0 and r is real. Suppose that w≠-z, that is, r≠0.
Remember this useful identity: if x is a complex number then
where
is the conjugate of x.
Now, using the properties of the conjugate (the conjugate of the sum(product) of two numbers is the sum(product) of the conjugates):

=
Thus
. From this,
. A complex number is real if and only if it is equal to its conjugate, therefore r is real.
Answer:
9
Step-by-step explanation:
5+4=9
The diameter of the base of the cone is 6 units, thus the radius of it is 3 then.
You have to multiply 6*5*4*3*2*1 so it will be 720
122 employees
Because
1/2 of 64 is 32
2/3 of 81 is 54
3/4 of 48 is 36
32+54+36=122