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slavikrds [6]
4 years ago
10

Evaluate the expression ( 1 + 2 i ) ( − 2 − 1 i ) and write the result in the form a + b i .

Mathematics
1 answer:
Nina [5.8K]4 years ago
6 0

Answer:

- 5i.

Step-by-step explanation:

( 1 + 2 i ) ( − 2 − 1 i )

= 1 * -2 + 1*-1i + 2i*-2 - 2i*1i

= -2 - i - 4i - 2i^2           i^2 = -1 so we have:

-2 - 5i +2

= 0 - 5i

= -5i.

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Your answer must be simplified.
JulijaS [17]

Answer:

The simplified form is x\geq -99.

Step-by-step explanation:

Given : Expression \frac{x}{3}\geq -33

To find : The simplified expression ?

Solution :

Expression \frac{x}{3}\geq -33

Multiply 3 both side,

\frac{x}{3}\times 3\geq -33\times 3

x\geq -99

Therefore, the simplified form is x\geq -99.

8 0
3 years ago
During the mayoral election,two debates were held between the candidates. The first debate lasted 1 2/3 hours.The second one was
butalik [34]

Answer:

2nd debate was 3 hours long.

Step-by-step explanation:

We have been given that during the mayoral election,two debates were held between the candidates. The first debate lasted 1 2/3 hours. The second one was 1 4/5 times as long as the first one.

Let us find the estimate of time spent on 2nd debate.

1 2/3 hours would be approximately 2 hours. 1 4/5 times would be equal to 2 times.

2*2=4

Therefore, the estimated time is less 4 hours.

To find the time spent on 2nd debate, we will multiply 1 2/3 by 1 4/5.

First of all, we will convert mixed fractions into improper fractions as:

1\frac{2}{3}=\frac{5}{3}

1\frac{4}{5}=\frac{9}{5}

Now, we will multiply both fractions as:

\frac{5}{3}\times \frac{9}{5}

\frac{1}{3}\times \frac{9}{1}

\frac{9}{3}\Rightarrow 3

Therefore, the 2nd debate was 3 hours long.

5 0
3 years ago
(Can somebody find the sum of this) <br><br><br> (5+2i)+(8-3i)
7nadin3 [17]
Hey there!!

Okay so here are the steps....

(5 + 2i) + (8 - 3i)       <---- when we have exponents we should worry about the                                            "i" because it is equal to √-1 but here it isn't the case.
<u>

(13 - i)</u>
<u />   <----- This is the answer!



<u />I hope this helps! ^__^
7 0
3 years ago
M(x) = 4x + 15; m(x) = 7
stealth61 [152]

Hi there! :)

\huge\boxed{x = -2}

m(x) = 4x + 15

Find the value of "x" that would satisfy m(x) = 7:

4x + 15 = 7

Subtract 15 from both sides:

4x = -8

Divide both sides by 4:

x = -2.

7 0
4 years ago
Two fifths times ten
babymother [125]
2/5 * 10 = 2/5 * 10/1 = 20/5 = 4

Answer is 4
8 0
3 years ago
Read 2 more answers
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