Evaluate 27x squared

Find the partial fraction decomposition of the rational expression with prime quadratic factors in the denominator

SpyIntel [72]

$\dfrac{5x^4-7x^3-12x^2+6x+21}{(x-3)(x^2-2)^2}=\dfrac{a_1}{x-3}+\dfrac{a_2x+a_3}{x^2-2}+\dfrac{a_4x+a_5}{(x^2-2)^2}$
$\implies 5x^4-7x^3-12x^2+6x+21=a_1(x^2-2)^2+(a_2x+a_3)(x-3)(x^2-2)+(a_4x+a_5)(x-3)$

When $x=3$ , you're left with

$147=49a_1\implies a_1=\dfrac{147}{49}=3$

When $x=\sqrt2$ or $x=-\sqrt2$ , you're left with

$\begin{cases}17-8\sqrt2=(\sqrt2a_4+a_5)(\sqrt2-3)&\text{for }x=\sqrt2\\17+8\sqrt2=(-\sqrt2a_4+a_5)(-\sqrt2-3)\end{cases}\implies\begin{cases}-5+\sqrt2=\sqrt2a_4+a_5\\-5-\sqrt2=-\sqrt2a_4+a_5\end{cases}$

Adding the two equations together gives $-10=2a_5$ , or $a_5=-5$ . Subtracting them gives $2\sqrt2=2\sqrt2a_4$ , $a_4=1$ .

Now, you have

$5x^4-7x^3-12x^2+6x+21=3(x^2-2)^2+(a_2x+a_3)(x-3)(x^2-2)+(x-5)(x-3)$
$5x^4-7x^3-12x^2+6x+21=3x^4-11x^2-8x+27+(a_2x+a_3)(x-3)(x^2-2)$
$2x^4-7x^3-x^2+14x-6=(a_2x+a_3)(x-3)(x^2-2)$

By just examining the leading and lagging (first and last) terms that would be obtained by expanding the right side, and matching these with the terms on the left side, you would see that $a_2x^4=2x^4$ and $a_3(-3)(-2)=6a_3=-6$ . These alone tell you that you must have $a_2=2$ and $a_3=-1$ .

So the partial fraction decomposition is

$\dfrac3{x-3}+\dfrac{2x-1}{x^2-2}+\dfrac{x-5}{(x^2-2)^2}$

7 0

3 years ago

PLEASE HELP. WILL GIVE BRAINLY

zepelin [54]

For these questions it is asking you to convert different measurements.
For the first part,
You must convert 10 kilometres to meters
Or 500 meters to kilometres
For this example I will covert 500 meters to kilometres
1000 meters = 1 kilometer
So 500 meters is 0.5 kilometres or half a kilometer
So on the first day you ride 10 kilometres and increase by 0.5 kilometres a day that means you increase by 1 kilometer every two days
The question is asking how many days until you get to 15 kilometres well
15-10=5
5x2 =10 so the answer to the first part is 10 days

In the second part you have to convert again I am going to convert kilometres to meters this time
We know 1km = 1000m
So you times the kilometer by 1000 to get the meters
0.75 x 1000 = 750
So you start with 7500 and increase by 750 every day
The question asks you the total after 3 days so we must find out each day and add them up
1st day: 7500
2nd day: 7500+750=8250
3rd day: 8250+750=9000
Now we must add them together so
7500+8250+9000=24750
So the answer to this part is 24750 meters

The last part is asking you to compare the programs so let’s start with training program A
20-10=10
10x2= 20
So A is 20 days

Training program B:
We know from previous questions that on the third day you do 9000 meters so we must carry on from there
4th day: 9000+750=9750
5th day: 9750 +750=10500
6th day: 10500 + 750=11250
7th day: 11250 + 750 = 12000
As you can see there is a pattern here on the 3rd day we are on 9000 and on the 7th day we are on 12000 that means it has increased by 3000 in 4 days this is because 750 x 4 = 3000
This means we know 18000 is the 15th day
We will carry on from here
16th day: 18000+750=18750
17th day: 18760+750=19500
18th day: 19500+750=20250
Here we have gone over 200000 which is 20 km on the 18th day meaning training program B is quicker

8 0

3 years ago

Laura drives a garbage truck that weighs 3 tons. She picked up 2 tons of recyclables. What is the total weight in pounds of the

Allushta [10]

Answer:

Step-by-step explanation:

Total weight=The garbage truck weight + recyclables weight =3 tons + 2 tons = 5 tons

3 0

3 years ago

Read 2 more answers

What is the probability that she does not draw a dance class?

Anon25 [30]

You aren’t giving any context to the question

4 0

3 years ago

What is the answer to 3(2-x)-2 if x equal -2

hoa [83]

Answer:

0.

Step-by-step explanation:

3(2-2)

Distribute 3 to -2 and you would get 6.

Then you would distribute 3 too -2 and get -6.

After, you would have 6-6, which is 0.

7 0

4 years ago

Evaluate 27x squared - 42x + 12