If the real part and imaginary part of complex 2-bi / 1 + 2I are opposite to each other, the value of B is obtained

If the real part and imaginary part of complex 2-bi / 1 + 2I are opposite to each other, the value of B is obtained

That is, the real part and imaginary part of (2-bi) (1-2i) are opposite to each other
Re=2-2b
Im=-b-4
So 2-2b = B + 4, B = - 2 / 3
The plural number 5 / 1 + I ^ 3 becomes a + bi. Note that it's one plus the letter I three times. Don't answer if you don't see clearly,
=5/(1+3*i+3*i²+i³)
=5/(1+3i-3-i)
=5/(-2+2i)
=5(-2-2i)/(-2+2i)(-2-2i)
=5(-2-2i)/(4+4)
=-5/4-(5/4)i
i^2=-1
i^3=-i
5/(1+i^3)=5/(1-i)=5(1+i)/(1+1)=5/2+5/2i
a=5/2 b=5/2
The noun, verb and phrase of "look"
Have a good look at
Look around
Look ahead
Look back
Look right / left
Look well
Look ill looks sick
In good looks
Look down on (up on)
Look over check
Look like
Look out
To look up (a dictionary)
Look down
Look up and down
Look into
Look for
Look after
1) Look around
The man kept looking about
(2) Look around, look around
A: What can I do for you, madam?
B: No, I'm just looking around
(3) Look everywhere
I'm looking about for a house
(4) Consider carefully
Look about carefully before making the decision
Take care of
I can look after myself
Who is looking after the luggage?
3. look at
(1) Look Look at For example:
He looked at me and smile
Look at him jump [jumping]
(2) For example:
That's the way I look at it
(3) Consider (a sentence with a negative meaning)
They refused to look at my suggestion
(4) Inspection, such as:
He came to look at the drainage
4. look back
(1) Look back on
I still shudder when I look back on the past
(2) To stop, shrink, regress (usually in a negative sentence)
From this time on, he never looked back
5. Look down on [up on]
You shouldn't look down on the poor
She likes tennis, but looks down on football
6. look for
(1) Look for
I've looked for it everywhere
You are looking for trouble
(2) Look forward to
We shall be looking for an improvement in your work this term
It's too soon yet to look for results
Look forward to
We're looking forward to hearing from you
The children are looking forward to your visit
Note: to in this structure is a preposition, not an infinitive sign, so when it is followed by a verb, gerund should be used instead of the original form of the verb
8. Look in
Why don't you look in (on) me next time you're in town?
I may look in at the party on my way home
9. Look into
We'll look into that right away
The police are looking into the cause of the accident
10. look like
(1) It looks like
He looks like your brother
What does he look like?
He looks like an honest man
(2) As if to, as if to
It looks like rain [raining]
He looks like winning
11. look on
(1) Look on
No, I'm not playing; I'm just looking on
(2) To see (wait for), esp with a certain look or emotion
She was looked on with distrust
(3) To regard as (with as)
He looks on me as his best friend
We looked on this as useless
12. look out
(1) Look out
Don't look out of the window
He stood at the window and looked out (at the view)
(2) Be careful, be careful, be careful
Look out. There's a car coming!
If you don't look out, you'll hurt yourself
(3) To find out or select
We looked out his address in, the telephone directory
13. Look over
Would you mind looking over my exercises?
He looked her over and nodded lightly（
14. Look through
Before the meeting he looked through the reports
Look through your notes before the examination
15. Look to
The country must look to its defenses
Look to it that this doesn't happen again
16. look up
(1) To look up
Look up this word in the dictionary
(2) To call on (a person)
I want to look up an old friend
(3) For example:
Things are looking up
17. Look up to respect
I look up to my parents
He is a good teacher. We've always looked up to him
Transitive verb vt. & Intransitive Verb VI
*Look, look
Look whether the postman has been yet.
Go and see if the postman has been.
Intransitive verb VI
*1. Face, face
The house looks south.
The house faces south.
... unfold
Transitive verb vt. & Intransitive Verb VI
*Look, look
Look whether the postman has been yet.
Go and see if the postman has been.
Intransitive verb VI
*1. Face, face
The house looks south.
The house faces south.
The offices look onto a park.
These offices face the park.
*2. Seek; seek
*Pay attention to
*4. With Similar in appearance; as if; as if
*It looks as if; it seems possible
*Facing; facing
Link-v
*1. It seems that
He looks an honest man.
He looks like an honest man.
He's beginning to look his age.
He looks his age.
She looks much younger than she is.
She looks much younger than her age.
She was looking her best.
She looked beautiful then.
He looked blank when he was informed of his dismissal.
He was at a loss when he was told he was fired.
It looks very suspicious to me.
I think it seems very unreliable.
They looked as if they didn't care.
They don't seem to care.
It looks as if it were going to rain.
It seems to rain.
It looks as if we were going to have fine weather.
It seems to be clearing up.
It looks as if there will be a strike.
There seems to be a strike.
It looks as if the coming autumn harvest will be even better than the last one.
It seems that the coming autumn harvest will be better than last year.
*2. Look as if
Noun n
*Look, glance
I took a close look at her photo.
I took a close look at her picture.
*2. Look in the eyes
She assumed a look of innocence.
She pretended to be innocent.
*(especially attractive) appearance, countenance, beauty
She used her good looks to compensate her lack of intelligence.
She used her beautiful appearance to make up for her lack of intelligence.
*4. Find
*5. Appearance
*6. Fashion; style; style
Interj
*Now, listen to me and put it away
vt. & vi.
Look, look
Look whether the postman has been yet.
Go and see if the postman has been.
Vi.
Face, face
The house looks south.
The house faces south.
The offices look onto a park.
These offices are open to
vt. & vi.
Look, look
Look whether the postman has been yet.
Go and see if the postman has been.
Vi.
Face, face
The house looks south.
The house faces south.
The offices look onto a park.
These offices face the park.
link v.
It seems that
He looks an honest man.
He looks like an honest man.
He's beginning to look his age.
He looks his age.
She looks much younger than she is.
She looks much younger than her age.
She was looking her best.
She looked beautiful then.
He looked blank when he was informed of his dismissal.
He was at a loss when he was told he was fired.
It looks very suspicious to me.
I think it seems very unreliable.
They looked as if they didn't care.
They don't seem to care.
It looks as if it were going to rain.
It seems to rain.
It looks as if we were going to have fine weather.
It seems to be clearing up.
It looks as if there will be a strike.
There seems to be a strike.
It looks as if the coming autumn harvest will be even better than the last one.
It seems that the coming autumn harvest will be better than last year.
N.
Look, glance
I took a close look at her photo.
I took a close look at her picture.
Face, look, expression
She assumed a look of innocence.
She pretended to be innocent.
Beauty
She used her good looks to compensate her lack of intelligence.
She used her beautiful appearance to make up for her lack of intelligence. Put it away
What did it get so out of hand?
Out of hand out of control
Why has it become so uncontrollable? Wild, HOHO~