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3 years ago

Multiply and simplify the following complex numbers: (1 + 2i) x (1 - 4i)

Mathematics

1 answer:

Ivanshal [37]3 years ago

6 0

Answer:

9-2i

Step-by-step explanation:

(1 + 2i) * (1 - 4i)

(1*1)-(1*4i)+(2i*1)-(2i)*(4i)

(1)-(4i)+(2i)-(8i^2)

i^2 = -1

1-4i+2i+8

1-2i+8

9-2i

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Please help me! Thank you!

Hunter-Best [27]

Answer:

Right triangles are never acute triangles.

Obtuse triangles are sometimes isosceles triangles.

Step-by-step explanation:

The first 2 answers you have included are correct.

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3 years ago

Rainfall collected in a rain gauge was found to be 2.3 cm when rounded to the nearest tenth of a centimeter.

Korolek [52]

Answer:

(a). 2.251 cm , 2.349 cm, 2.295 cm

(b). 0.023 meters.

Step-by-step explanation:

(a). We are asked to to choose the options that shows the actual measurement of the rainfall.

Since the rounded figure is 2.3 cm, this means that either the tenths digit is 3 with hundredths digit less than 5, or tenths digit is 2 with hundredths digit greater than or equal to 5.

Let us check our given choices one by one.

$2.251\text{ cm}\approx 2.3\text{ cm}$

$2.349\text{ cm}\approx 2.3\text{ cm}$

$2.352\text{ cm}\approx 2.4\text{ cm}$

$2.295\text{ cm}\approx 2.3\text{ cm}$

Therefore, the correct choices are 2.251 cm , 2.349 cm and 2.295 cm.

(b) We know that 1 cm equals 0.01 meters.

To convert 2.3 cm to meters, we will multiply 2.3 by 0.01.

$2.3\text{ cm}=2.3\text{ cm}\times \frac{0.01\text{ meters}}{\text{cm}}$

$2.3\text{ cm}=0.023\text{ meters}$

Therefore, the rounded measurement of rain would be 0.023 meters.

8 0

4 years ago

xavier sells homemade necklaces for a profit of $22 per necklace. he is considering switching to a new type of pendant that will

NikAS [45]

Answer:

29 dollars each

6 0

3 years ago

Read 2 more answers

Find the value of x a. 7.5 b. 6 c. 10 d. 8

Radda [10]

B.6 because the length is equal to the length of the other 6

7 0

3 years ago

If x= 5 and y = 2, work out the value of a) 3x + y b) 2x2 c) (x - y)2

Oxana [17]

Answer:

17, 50, 9

Step-by-step explanation:

Hello

We already know the values of x and y, 5 and 2.

All we have to do to figure out a, b, and c, is to plug in those known values.

a) 3x + y

Let's plug in x and y as 5 and 2

3(5) + 2

15 + 2

b) 2x^2

2(5)^2

2(25)

c) (x - y)^2

(5 - 2)^2

3^2

5 0

3 years ago

Read 2 more answers