Find the coefficient of x^4 in the expansion of (x−9)^8 Please I need help!!

Mathematics

1 answer:

alexdok [17]2 years ago

5 0

Answer:

459270

is the coefficient

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G=x-c/x. for x how do yoy make this an equation for x? help

zzz [600]

1.
$\displaystyle \text{if }\quad G=x- \frac{C}{x} \\\\$

$x \neq 0$

Multiply both sides by x:

$\displaystyle Gx=x\bigg(x- \frac{C}{x}\bigg )\\\\Gx=x^2-C$

Subtract from both sides Gx:
$Gx-Gx=x^2-C-Gx\\x^2-Gx-C=0$

Then solve this equation:

$\displaystyle x^2-Gx-C=0\\\\x_{1,2}= \frac{G\pm \sqrt{G^2+4C} }{2}$

2.
$\displaystyle\text{if}\quad G= \frac{x-C}{x}$

$x \neq 0$

Multiply both sides by x:

$Gx=x-C$

Subtract from both sides Gx:

$x-C-Gx=0$

Then solve this equation:

$\displaystyle x-Gx-C=0\\x(1-G)=C\\x= \frac{C}{1-G}$

7 0

2 years ago

The period T of a pendulum in seconds depends on its length L in feet, and is given by the formula T=

Damm [24]

This is a matter of plugging in. Specifically 7 for L.

T = 2πsqrt(7/32)
T = (6.28319...)(0.46771...)
T is about 2.93871 seconds

4 0

2 years ago

If 1 is added to a number and the sum is tripled, the result is 17 more than the number. Find the number

bearhunter [10]

Form an equation. Start by representing the number you want to find as X. Now add 1.
X + 1
Now we need to triple it. That basically means multiply X+1 by 3. You can write that as:
3 (X + 1)
Now we write out that the result is 17 more than the number we want to find. So set an equals sign up
3 (X + 1) =
And now write X + 17
3 (X + 1) = X + 17

Now we solve for X.
Firstly, let's get rid of the X on the right.
Remember, if we want to get rid of a number of variable on one side, we need to use opposites, and do the same to the other side of the equation.
In this case, we have a positive X on the right. To get rid of that, we subtract X from both sides. This will leave us with:
2x + 3 = 17
Now let's get rid of the +3 on the left. To do this, we subtract 3 from both sides of the equation.
2x = 17 - 3
2x = 14
Now we just need to get X by itself. The 2 in front of the X multiplies X by 2. Therefore, to get X on its own, we need to divide 2x by 2, which just gives us 2.
We also need to divide the other side by 2, because if we do something on one side, we need to do something on the other too. So divide 14 by 2, and we get 7.
X = 7

But before we celebrate, let's double check the answer. Add 1 to 7. This gives us 8. Triple 8. This is 24. This should be 17 more than 7. So go, 24 - 17. And whaddya know - it's 7!