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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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Csc α - sin α =cos α cot α<br> Show how this is an identity?
Savatey [412]
Csc a - sin a = cos a cot a
1/sin a - sin a = cos a (cos a / sin a)
(1 - sin^2 a)/sin a = cos^2 a/sin a
cos^2 a/sin a = cos^2 a/sin a

Therefore, the given equation is an identity.
8 0
3 years ago
Y = 15x + 10, where y is the total cost of renting 1 bicycle on the boardwalk for x hours. Determine whether the function is pro
vova2212 [387]

Answer:

The function is non-proportional.

Step-by-step explanation:

If the function was proportional, when the number of hours spent riding the bicycle is equal to 0, the total cost of renting the bicycle would also be 0. In other words, the function would be proportional if y=0 when x=0. However, this is not the case.

y=15x+10

Plug 0 into the equation as x

y=15(0)+10\\y=10

When 1 bicycle has been rented for 0 hours, the customer still has to pay 10 dollars just for renting it. When x=0, y=10. This means that the function is non-proportional.

I hope this helps!

4 0
3 years ago
What is<br> 5 1/6 - 5 1/2
Ymorist [56]

Answer:

1/3

Step-by-step explanation:

51/6 = 51/6

51/2= 5 3/6

= 2/6

6 0
3 years ago
Read 2 more answers
When multiplied together, which two polynomials equal ab3+2a2b2? Select the two correct answers.
fomenos
The answer is 2) ab2 that would be ur answer
5 0
3 years ago
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What is the slope of the graph of 14x + 7y = –9? A. 1/2 B. -1/2 C. 2 D. -2
Debora [2.8K]
First move the 14x over to get 7y=-14x-9 then divide by 7 and you get y= -2x-9/7. the slope is the value next to the x in y=mx+b form so the slope is -2
7 0
4 years ago
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