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3 years ago

What is the coefficient of x4 in the expansion of (3x + 1)??

Mathematics

1 answer:

bulgar [2K]3 years ago

7 0

It would be O 945 that is the answer

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The length of a rectangle is three feet less than twice its width. If x represents the width of the rectangle, in feet, write in

Cerrena [4.2K]

Answer:

x>30.meaning that the x is greater than 30

3 0

3 years ago

A fisherman traveled in a boat from point N upstream. After having traveled 6 km, he stopped rowing and 2 hour 40 min after firs

Nat2105 [25]

Answer:

The speed of the river's current is 4.5 km/hr.

Step-by-step explanation:

Given : A fisherman traveled in a boat from point N upstream.

After having traveled 6 km, he stopped rowing and 2 hour 40 min after first leaving N, he was brought back to N by the current.

Knowing that the speed of the boat in still water is 9 km/hour

To find : The speed of the river’s current.

Solution :

Let the speed of current = x km/h

Speed of boat = 9 km/h

Thus, the speed in upstream = (9 - x) km/h

Also, the speed in downstream = x km/h (because the boat is stationary in downstream)

Total distance = 6 km ( from N to the point he reached )

Total time = 2 hours 40 minutes

$\text{2 hours 40 minutes}=2\frac{40}{60}=2 \frac{2}{3} \\\\\text{2 hours 40 minutes}=\frac{8}{3} \text{ hours}$

We know, $\text{Time} = \frac{\text{Distance}}{\text{Speed}}$

According to the question,

$\frac{6}{9-x}+\frac{6}{x}=\frac{8}{3}$

Taking LCM and 6 common

$6[\frac{x+9-x}{(9-x)x}]=\frac{8}{3}$

Take 6 to another side,

$\frac{9}{9x-x^2}=\frac{8}{3\times 6}$

Cross multiply,

$9\times 18=8\times(9x-x^2)$

$162=72x-8x^2$

Taking 4 common and cancel out

$4x^2-36x+81=0$

Solve quadratic equation by middle term split,

$4x^2-18x-18x+81=0$

$2x(2x-9)-9(2x-9)=0$

$(2x-9)(2x-9)=0$

$\Rightarrow 2x-9=0$

$\Rightarrow x=\frac{9}{2}=4.5$

Therefore, The speed of the river's current is 4.5 km/hr.

6 0

3 years ago

-4 + 4 <br> Same signs? <br> Different sign?<br> Add/Subtract?

marin [14]

Answer:

Step-by-step explanation:

-4 is negative 4 witch is less then 4. -4 +4 =0

4 0

3 years ago

Read 2 more answers

Trish runs 3 miles every 50 minutes. At this rate, how many minutes did Trish tun 12 miles? plzzz help me!!!

Alika [10]

50 x 4 = 200 minutes

The reason why I multiplied by 4 was because 12 divide 3 = 4

200 minutes is equal to 3 hours 20 minutes
There's your answer

Hope this helps!

7 0

3 years ago

Read 2 more answers

Which is greater? 0.006 or 0.1

frez [133]

Answer:

0.1

Step-by-step explanation:

In a problem like this the number that is more to the left is greater. As you can see 0.1 is more to the left

5 0

3 years ago