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Lorico [155]
3 years ago
11

What is the value of (7 + 2i)(3 - i)?

Mathematics
1 answer:
Harrizon [31]3 years ago
7 0
There are two ways to work this out: normal variables or using "imaginary" numbers.

Normal variables:
(7+2i)(3-i)\\(7*3)+[7*(-i)]+(3*2i)+[2i*(-i)]\\21-7i+6i-2i^{2}\\\\21-i-2i^{2}

Imaginary numbers:
Using the result from earlier:
21-i-2i^{2}
Now since i = \sqrt{-1}, then the expression becomes:
21-i-2i^{2}\\21-i-2(\sqrt{-1})^{2}\\21-i+(-2)(-1)\\21-i+2\\\\23-i
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Julian used these steps to solve the equation 9x=?6+3(3x+2) 9 x = - 6 + 3 ( 3 x + 2 ) . Which choice describes the meaning of hi
Rashid [163]

Answer:

see explanation

Step-by-step explanation:

the result 0 = 0

means the equation has an infinite number of solutions


7 0
3 years ago
Read 2 more answers
How much heat in kJ is released when nitrogen and hydrogen react as below to form 100.g ammonia heat equals-92.2kj
tresset_1 [31]

100g of ammonia releases 271.18 kJ of heat.

<u>Explanation:</u>

Given:

N₂ reacts with H₂

The reaction is:

2N₂ + 3H₂ → 2NH₃ + 92.2 kJ

According to the balanced reaction:

2 X 17g of ammonia releases 92.2 kJ of heat

34g of ammonia releases 92.2 kJ of heat

100g of ammonia will release = \frac{92.2}{34} X 100 kJ of heat

                                                 = 271.18 kJ

Therefore, 100g of ammonia releases 271.18 kJ of heat.

8 0
3 years ago
Select the correct answer from each drop-down menu.
german

5 is a coefficient.  A coefficient is a number multiplied by a variable.


(2y+13) is a factor.  It can be multiplied by 8 to get an extended answer.


-1 is a constant.  A constant is a number that does not change.


Hope this helps!

7 0
3 years ago
Read 2 more answers
The joint probability mass function of XX and YY is given by p(1,1)=0p(2,1)=0.1p(3,1)=0.05p(1,2)=0.05p(2,2)=0.3p(3,2)=0.1p(1,3)=
inessss [21]

Answer:

P(Y=1|X=3)=0.125

Step-by-step explanation:

Given :

p(1,1)=0  

p(2,1)=0.1

p(3,1)=0.05

p(1,2)=0.05

p(2,2)=0.3

p(3,2)=0.1

p(1,3)=0.05

p(2,3)=0.1

p(3,3)=0.25

Now we are supposed to find the conditional mass function of Y given X=3 :  P(Y=1|X=3)

P(X=3) = P(X=3,Y=1)+P(X=3,Y=2) +P(X=3,Y=3)

P(X=3)=p(3,1) +p(3,2) +p(3,3)

P(X=3)=0.05+0.1+0.25=0.4

P(Y=1|X=3)=\frac{P(X=3,Y=1)}{P(X=3)} =\frac{p(3,1)}{P(X=3)}=\frac{0.05}{0.4}= 0.125

Hence P(Y=1|X=3)=0.125

8 0
3 years ago
Answer this question please :)
Aleonysh [2.5K]

Answer:

Step-by-step explanation:

9*7=63

63

triangle area=21

63+21=84

7 0
3 years ago
Read 2 more answers
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