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2 years ago

Subtract 7a2-4ab+2b2from 3ab+7a2+2b2

Mathematics

1 answer:

LUCKY_DIMON [66]2 years ago

4 0

Answer:

Step-by-step explanation:

3ab + 7a² + 2b² - (7a² - 4ab + 2b²) = 3ab + 7a² + 2b² - 7a² + 4ab - 2b²

Now combine like term. Like terms have same variable with same power.

= 3ab + 4ab + 7a² - 7a² + 2b² - 2b²

= 7ab

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3x−(2x+1) for x=7 5/13

marusya05 [52]

Answer:

83/13 or 6.3846

Step-by-step explanation:

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3 years ago

The school sold $6000 worth of tickets. Adult tickets were seven dollar and children’s tickets were three dollars. Three times a

padilas [110]

Answer:

1,500 tickets in total (375 adult tickets and 1,125 children tickets)

Step-by-step explanation:

Let x be the number of adult tickets sold.

Three times as many children tickets were sold as adults, so 3x is the number of children tickets sold.

Children tickets were three dollars, so 3x children tickets cost $\$3\cdot 3x=\$9x.$

Adult tickets were seven dollar, so x adult tickets cost $\$7\cdot x=\$7x.$

The school sold $6000 worth of tickets.

Hence,

$9x+7x=6,000\\ \\16x=6,000\\ \\x=\dfrac{6,000}{16}=375\\ \\3x=1,125\\ \\x+3x=375+1,125=1,500$

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3 years ago

An SRS of size 20 is drawn from a population that has a normal distribution. The sample has a mean of 122.5 and a standard devia

Tems11 [23]

Answer:

The value is $\sigma_{\= x} = 1.789$

Step-by-step explanation:

From the question we are told that

The sample size is n = 20

The sample mean is $\= x = 122.5$

The standard deviation is $s = 8$

Generally the standard error of the mean is mathematically represented as

$\sigma_{\= x} = \frac{s}{\sqrt{n} }$

=> $\sigma_{\= x} = \frac{8}{\sqrt{20 } }$

=> $\sigma_{\= x} = 1.789$

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3 years ago

A train leaves San Diego at 1:00 pm. A second train leaves the same city in the same direction at 3:00 pm. The second train trav

Soloha48 [4]

Answer:

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Step-by-step explanation:

Let x represent the speed of the first train in mph. Since the second train, is 30 mph faster then the first, therefore the speed of the second train is (x + 30).

The first train leaves at 1:00 pm, therefore at 6:00 pm, the time taken is 5 hours. Therefore the distance covered by the first train at 6:00 pm = x mph * 5 hours = 5x miles

The second train leaves at 3:00 pm, therefore at 6:00 pm, the time taken is 3 hours. Therefore the distance covered by the second train at 6:00 pm = (x + 30) mph * 3 hours = (3x + 90) miles

Since the second train overtakes the first at 6:00 pm, hence:

3x + 90 = 5x

2x = 90

x = 45

Therefore the speed of the first train is 45 mph and the speed of the second train is 75 mph (45 mph + 30 mph).

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3 years ago

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Delicious77 [7]

Answer:

Step-by-step explanation:

Use the HL Congruence Theorem to prove that the triangles are congruent.

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3 years ago