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3 years ago

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

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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Answer:

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2 years ago

which method for comparing fractions were you unaware of before reading? use it to compare 2/3 and 3/4

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Good morning

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Answer:

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3 years ago

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2 years ago

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Cerrena [4.2K]

The table have the following results:

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Diamonds – 4

Clubs – 8

Spades – 5

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