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3 years ago

20 times 1/2 I don't know what th8s means can you help

Mathematics

2 answers:

Natalka [10]3 years ago

5 0

Multiplying 20×1/2 is the same as dividing 20 by 2. Which means the answer is 10.

nignag [31]3 years ago

4 0

20 times 1/2 is 10, because half of 20 is 10

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Which set of ordered pairs represents a function?

Katen [24]

Answer: A)
The first one because the x don’t repeat

3 0

3 years ago

Let $a$ and $b$ be nonzero real numbers such that

algol [13]

<h3>Answer: -7/2</h3>

=========================================================

Explanation:

Let's expand out (2 - 7i)(a + bi) using the FOIL rule

(2 - 7i)(a + bi) = 2a + 2bi - 7ai - 7bi^2

(2 - 7i)(a + bi) = 2a + 2bi - 7ai - 7b(-1)

(2 - 7i)(a + bi) = 2a + 2bi - 7ai + 7b

(2 - 7i)(a + bi) = (2a+7b) + (2bi-7ai)

(2 - 7i)(a + bi) = (2a+7b) + (2b-7a)i

We're told the result is purely imaginary. What this means is that the real part (2a+7b) is zero, while the imaginary part (2b-7a) is nonzero. If both are zero, then we have 0+0i = 0 which is purely real.

For example, the complex numbers 0-7i and 0+2i are purely imaginary.

Let's use the fact that 2a+7b must be zero to do the following steps:

2a+7b = 0

2a = -7b

a = -7b/2

a/b = -7/2 which is the final answer

We must check to see if 2b-7a is nonzero

2b - 7a = 2b - 7(-7b/2)

2b - 7a = 2b + 24.5b

2b - 7a = 26.5b

The result is nonzero if and only if b is nonzero. Luckily we're told b is nonzero at the top of the problem. So we don't have any worries that (2b-7a) is zero.

Therefore, (2a+7b) + (2b-7a)i will be purely imaginary with a/b = -7/2

------------------

A concrete example:

Let a = -14 and b = 4

a/b = -14/4 = -7/2

(2-7i)(a+bi) = (2-7i)(-14+4i) = 0 + 106i which is purely imaginary.

I'll let you do the steps in expanding that out using the FOIL rule.

4 0

1 year ago

Find x and the perimeter of the triangle. <br><br> x= <br> perimeter=

agasfer [191]

Answer:

x = 10 Perimeter: 129

Step-by-step explanation:

FINDING X:

4x+7 = 5x -3

7 = x -3

10 = x

x = 10

PERIMETER:

4x + 7 + 5x - 3 + 4x - 5

Combine the "x" values

13x + 7- 3 - 5

Combine the numbers

13x - 1

13(10) -1

130 - 1

129

3 0

2 years ago

Read 2 more answers

At the end of April, Mandy told Bill that she has read 16 books this year and reads 2 books each month. Bill wants to catch up t

klemol [59]

Mandy Increases her books by 2 per month.
Bill increases his books by 4 per month.

Month Mandy Bill
May 18 4
June 20 8
July 22 12
August 24 16
Sept 26 20
Oct 28 24
Nov 30 28
Dec 32 32
At the end of December they will have read the same amount of books.

6 0

3 years ago

Read 2 more answers

Ms. drake invests $1000 at a simple interest rate of 8.5% for 2 years. how much interest will she earn in this time?

PilotLPTM [1.2K]

Ms. Drake will earn $\$ 170$ in this time from the investment of $\$ 1000$ at a simple interest with rate of interest $8.5\%$

<h3>What is the definition of simple interest?</h3>

Simple interest is a way to figure out how much interest will be charged on a sum of money at a specific rate and for a specific duration of time. Conversely, for compound interest, where we add the interest of one year's principal to the next year's principal to compute interest, the principal amount under simple interest remains constant.

Formula for finding simple interest is $\frac{principal \times rate \ of \ interest \times time}{100}$