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4 years ago

Whats the difference of the two expression? (3/7x+9)-(2/7x-3)

1 answer:

4 0

$\left(\frac{3}{7}x+9\right)-\left(\frac{2}{7}x-3\right)\\\\=\frac{3}{7}x+9-\frac{2}{7}x-(-3)\\\\=\frac{3}{7}x+9-\frac{2}{7}x+3\\\\=(\frac{3}{7}x-\frac{2}{7}x)+(9+3)\\\\=\frac{3-2}{7}x+12\\\\=\boxed{\frac{1}{7}x+12}$

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Two sides of a triangle are 12 and 18 cm. Complete the inequality to show the possible lengths of the third side.

musickatia [10]

Let a = 12 and b = 18 be the two given sides

Let c be the unknown third side

Due a modified form of the triangle inequality theorem, we know that,

b-a < c < b+a

18-12 < c < 18+12

6 < c < 30 which is the final answer

This says c is between 6 and 30, but cannot equal either endpoint.

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3 years ago

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Alex787 [66]

He runs 6 miles... 1/6 hour for 1 mile equals 1 hours for 6 miles

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Dmitry_Shevchenko [17]

Answer:

y=4x-1

Step-by-step explanation:

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3 years ago

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Two college roommates have each committed to donating to charity each week for the next year. The roommates’ weekly incomes are

schepotkina [342]

Answer:

C. 5 weeks.

Step-by-step explanation:

In this question we have a random variable that is equal to the sum of two normal-distributed random variables.

If we have two random variables X and Y, both normally distributed, the sum will have this properties:

$S=X+Y\\\\\ \mu_S=\mu_X+\mu_Y=30+60=90\\\\\sigma_S=\sqrt{\sigma_X^2+\sigma_Y^2}=\sqrt{10^2+20^2}=\sqrt{100+400}=\sqrt{500}=22.36$

To calculate the expected weeks that the donation exceeds $120, first we can calculate the probability of S>120:

$z=\frac{S-\mu_S}{\sigma_S} =\frac{120-90}{22.36}=\frac{30}{22.36}=1.34\\\\P(S>120)=P(z>1.34)=0.09012$

The expected weeks can be calculated as the product of the number of weeks in the year (52) and this probability:

$E=\#weeks*P(S>120)=52*0.09012=4.68$

The nearest answer is C. 5 weeks.

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3 years ago

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Oksana_A [137]

Answer:

16.9

Step-by-step explanation:

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