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3 years ago

13

1st term in expansion of (x - y)

1 answer:

Andreas93 [3]3 years ago

7 0

Step-by-step explanation:

x y is the the side of the perimeter if u know what I mean

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A rectangle has a length of

Marina CMI [18]

rectangle has a length of

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3 years ago

PLEASE EXPLAIN !!!!!!!!!!!! Sophia has $2.25. she wants to give an equal amount. to each of her 3 young cousins. How much will e

stepladder [879]

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5 0

3 years ago

Read 2 more answers

How many pounds of a 15% copper alloy must be mixed with 700lb of a 30% copper alloy to maybe a 25.5% copper alloy

lisov135 [29]

Answer:

$300\; \rm lb$ .

Step-by-step explanation:

Let $x$ represent the mass (in pounds) of that $15\%$ copper alloy required, such that the final mixture would contain $25.5\%$ copper by mass.

Consider: if $x$ pounds of that $15\%$ copper alloy is mixed with $700$ pounds that $30\%$ copper alloy, what would be the mass of copper in the mixture?

Mass of copper in $x$ pounds of that $15\%$ copper alloy: $(0.15\, x)\; \rm lb$ .
Mass of copper in $700$ pounds of that $30\%$ copper alloy: $700 \times 0.30 = 210\; \rm lb$ .

Therefore, the mixture would contain $(210 + 0.15\, x) \; \rm lb$ of copper.

The mass of that mixture would be $(700 + x)\; \rm lb$ . The mass fraction of copper in that mixture would be:

$\displaystyle \frac{(210 + 0.15\, x)\; \rm lb}{(700 + x)\; \rm lb} \times 100\%$ .

This ratio is supposed to be equal to $25.5\%$ . These two pieces of equations combine to give an equation about $x$ :

$\displaystyle \frac{(210 + 0.15\, x)\; \rm lb}{(700 + x)\; \rm lb} \times 100\% = 25.5\%$ .

$\displaystyle \frac{210 + 0.15\, x}{700 + x} = 0.255$ .

Simplify and solve for $x$ :

$210 + 0.15\, x= 0.255\, (700 + x)$ .

$(0.255 - 0.15)\, x= 210 - 0.255 \times 700$ .

$\displaystyle x = \frac{210 - 0.255 \times 700}{0.255 - 0.15} = 300$ .

Therefore, $300\; \rm lb$ of that $15\%$ alloy would be required.

4 0

3 years ago

y=−2x−5 y=2x−2

Anettt [7]

Answer:

work is shown and pictured

7 0

3 years ago

Please help me as soon as posable!! In hurry!!(24 points)

attashe74 [19]

The sequence is geometric, so

$a_n = r a_{n-1}$

for some constant r. From this rule, it follows that

$a_3 = r a_2 \implies 20 = 2r \implies r = 10$

and we can determine the first term to be

$a_2 = r a_1 \implies 2 = 10 a_1 \implies a_1 = \dfrac15$

Now, by substitution we have

$a_n = r a_{n-1} = r^2 a_{n-2} = r^3 a_{n-3} = \cdots$

and so on down to (D)

$a_n = r^{n-1} a_1 = 10^{n-1} \cdot \dfrac15$

(notice how the exponent on r and the subscript on a add up to n)

4 0

2 years ago