First you must have the quadratic equal to zero. In order to do this you must subtract 7 to both sides
x^2 + 20x + (100 - 7) = 7 - 7
x^2 + 20x + 93 = 0
Now you must find two numbers who's sum equals 20 and their multiplication equal 93
Are there any? NO!
This means that you have to use the formula:

In this case:
a = 1
b = 20
c = 93



^^^We must simplify √28
√28 = 2√7
so...

simplify further:

-10 + √7
or
-10 - √7
***plus/minus = ±
Hope this helped!
~Just a girl in love with Shawn Mendes
Answer:

We can find the second moment given by:

And we can calculate the variance with this formula:
![Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246](https://tex.z-dn.net/?f=%20Var%28X%29%20%3DE%28X%5E2%29%20-%5BE%28X%29%5D%5E2%20%3D%207.496%20-%282.5%29%5E2%20%3D%201.246)
And the deviation is:

Step-by-step explanation:
For this case we have the following probability distribution given:
X 0 1 2 3 4 5
P(X) 0.031 0.156 0.313 0.313 0.156 0.031
The expected value of a random variable X is the n-th moment about zero of a probability density function f(x) if X is continuous, or the weighted average for a discrete probability distribution, if X is discrete.
The variance of a random variable X represent the spread of the possible values of the variable. The variance of X is written as Var(X).
We can verify that:

And 
So then we have a probability distribution
We can calculate the expected value with the following formula:

We can find the second moment given by:

And we can calculate the variance with this formula:
![Var(X) =E(X^2) -[E(X)]^2 = 7.496 -(2.5)^2 = 1.246](https://tex.z-dn.net/?f=%20Var%28X%29%20%3DE%28X%5E2%29%20-%5BE%28X%29%5D%5E2%20%3D%207.496%20-%282.5%29%5E2%20%3D%201.246)
And the deviation is:

Answer:
b=-3
Step-by-step explanation:
-7b=21
-7b/-7=21/-7
b=-3
Answer:
In the given figure the point on segment PQ is twice as from P as from Q is. What is the point? Ans is (2,1).
Step-by-step explanation:
There is really no need to use any quadratics or roots.
( Consider the same problem on the plain number line first. )
How do you find the number between 2 and 5 which is twice as far from 2 as from 5?
You take their difference, which is 3. Now splitting this distance by ratio 2:1 means the first distance is two thirds, the second is one third, so we get
4=2+23(5−2)
It works completely the same with geometric points (using vector operations), just linear interpolation: Call the result R, then
R=P+23(Q−P)
so in your case we get
R=(0,−1)+23(3,3)=(2,1)
Why does this work for 2D-distances as well, even if there seem to be roots involved? Because vector length behaves linearly after all! (meaning |t⋅a⃗ |=t|a⃗ | for any positive scalar t)
Edit: We'll try to divide a distance s into parts a and b such that a is twice as long as b. So it's a=2b and we get
s=a+b=2b+b=3b
⇔b=13s⇒a=23s
Answer:
&jjuuuu8p788
Step-by-step explanation:
I am not sure if you are aware but the last night of our meeting was about to be around the same