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3 years ago

99 POINTS

Mathematics

2 answers:

Alik [6]3 years ago

6 0

Answer:

-a^2 - a + 12

Step-by-step explanation:

You only need to find the products of the first and last terms to determine the correct answer:

(-a)(a) = -a^2

(3)(4) = 12

You're looking for an expression with -1 as the leading coefficient and +12 as the constant. There is only one choice like that:

-a^2 - a + 12

Viktor [21]3 years ago

4 0

Answer: -a^2 - a + 12

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TiliK225 [7]

Answer: The answer is -x+7

Step-by-step explanation:

Multiply the numbers 2 * 2=4

=4x-5x+7

Add similar evidence 4x + -5x =-x

-x+7

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3 years ago

The circumference of a circle is 60 cm. What is the diameter

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<em>Using the formulas</em>

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2 years ago

Find the general solution of x'1 = 3x1 - x2 + et, x'2 = x1.

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Note that if ${x_2}'=x_1$ , then ${x_2}''={x_1}'$ , and so we can collapse the system of ODEs into a linear ODE:

${x_2}''=3{x_2}'-x_2+e^t$
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which is a pretty standard linear ODE with constant coefficients. We have characteristic equation

$r^2-3r+1=\left(r-\dfrac{3+\sqrt5}2\right)\left(r+\dfrac{3+\sqrt5}2\right)=0$

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${x_2}_C=C_1e^{(3+\sqrt5)/2\,t}+C_2e^{-(3+\sqrt5)/2\,t}$

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and so

$ae^t-3ae^t+ae^t=-ae^t=e^t\implies a=-1$

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3 years ago

14. (10pts) Consider the outward flux || Fonds where F = [01: 1, 2 ] and the surface S is the portion of the

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Answer:

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Step-by-step explanation:

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2 years ago

Annie’s change purse contained 5 quarters 8 dimes and 8 nickels if Annie chose 2 coin randomly without replacing them in her pur

Bogdan [553]

<h3>Answer:</h3>

2/15

<h3>Explanation:</h3>

There are 8C2 = 28 ways to choose 2 dimes from the 8 dimes in Annie's purse. There are 21C2 = 210 ways to choose 2 coins from the 21 coins in Annie's purse.

Of the 210 ways to choose 2 coins, 28 of the choices will result in 2 dimes being chosen. The probability of choosing 2 dimes is 28/210 = 2/15.

_____

<em>Comment on nCk</em>

The number of ways to choose k objects from n, when order does not matter, is ...

... n!/(k!(n -k)!)

For the computations above, we have ...

... 8C2 = 8·7/(2·1) = 28

... 21C2 = 21·20/(2·1) = 210

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3 years ago