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3 years ago

12

Use the Binomial Theorem to expand each binomial (5x-4y)^3

1 answer:

jek_recluse [69]3 years ago

5 0

You should know that:

(a+b)(a+b)(a+b)

=a(a+b)(a+b)+b(a+b)(a+b)

=a(a²+2ab+b²)+b(a²+2ab+b²)

=a³+2a²b+ab²+a²b+2ab²+b³

=a³+3a²b+3ab²+b³

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

If a=5x and b=-4y

(5x+(-4y))³

=(5x-4y)³

=(5x)³+3(5x)²(-4y)+3(5x)(-4y)²+(-4y)³

=125x³+3(25x²)(-4y)+15x(16y²)-64y³

=125x³+75x²(-4y)+240xy²-64y³

=125x³-300x²y+240xy²-64y³

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A carnival is being set up in your hometown. From experience, the carnival organizer knows that the amount of money he will brin

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Answer:

$6,200

Step-by-step explanation:

The question is to find the expected value.

We know the expected value of a scenario is the sum of the products of each probability of event and its profit or loss.

There are 3 probabilities in the scenario:

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Sunny: 50% = 50/100 = 0.5

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Now, the gain and loss is:

Rainy: Lose 5000 means -5000

Cloudy: Gain 4000 means +4000

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3 years ago

A pond has 150 fish and the population decreases by 8% each day. How many days before there are 30 fish

nlexa [21]

Answer:

19 days

Step-by-step explanation:

Given

$a = 150$ --- initial

$r = 8\%$ -- rate

Required

Days when the fish gets to 30

The function is exponential and as such it follows;

$y = ab^x$

Where x represents the number of days and y the number of fishes

Because the fishes decreases;

$b = 1 - r$

So, we have:

$b = 1 - 8\%$

Express as decimal

$b = 1 - 0.08$

$b = 0.92$

In $y = ab^x$

$a =150$

$y = 30$

$b = 0.92$

So, we have:

$30 = 150 * 0.92^x$

Divide both sides by 150

$0.2 = 0.92^x$

Take log of both sides

$log(0.2) = log(0.92^x)$

Apply law of logarithm

$log(0.2) = x\ log(0.92)$

Make x the subject

$x = \frac{log(0.2)}{log(0.92)}$

$x = \frac{-0.6990}{-0.0362}$

$x = 19.309$

$x \approx 19$

<em>Hence, it takes approximately 19 days</em>

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Answer:

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Step-by-step explanation:

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3 years ago

Read 2 more answers

Confusedddddddddddddddd

Elina [12.6K]

4x + 4 + 4x = 180 so solve for x and it’s 22
1. 4x + 4
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2. 88

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3 years ago