There are different ways to solve a quadratic equation, the main ones that i'm thinking about right now are:
1) factor the equation as a product:
ex: x^2+ 4x + 3 =0
(x+3) (x+1) = 0
x=-3 and x=-1 are the solutions.
To find (x+p) and (x+q) you have to think that (p+q )have to be equal to the number that is multiplied by x, in my example it was 4 (3+1=4), (p times q) have to be equal to the last number of the quadratic equation, the one that is not multiplied by any x, that in my example is 3 (3 x 1= 3)
2) The other way to solve a quadratic function is by using a formula:
given: ax^2 +bx +c=0
x= (-b +/- <span>√(b^2 -</span> 4ac)) / 2a
ex: 3x^2 + 4x -2=0
x= (-4 +/- √16-4(3)(-2)) / 6= (-4 +/- √16+24)/6= (-4 +/- <span>√40) / 6
now there are 2 possibilities: x= (-4+</span><span>√40) /6
and
x= (-4 - </span><span>√40) / 6
I hope the examples were clear enough also if i did't get very nice numbers. Look closely to the sings + and -, they are very important</span>
The ? is 1.
7*(9*1)=63
Hope this helps!!
Well, you would find the perimeter adding up all of the sides. Would you please tell us what each of the sides are, or what sides are what? :)
Considering the number of questions incorrect from classmates on a quiz {10, 11, 12, 13, 13, 13, 14, 15, 16, 16, 17, 18, 18, 19,
IrinaK [193]
Answer:
According to the Empirical Rule, 68% of the data should fall between 11.98 and 18.02
Step-by-step explanation:
We are given the following data in the question:
10, 11, 12, 13, 13, 13, 14, 15, 16, 16, 17, 18, 18, 19, 20
Formula:
where 
are data points, 
is the mean and n is the number of observations.
Sum of squares of differences = 25 + 16 + 9 + 4 + 4+ 4 + 1 + 0+ 1+ 1 + 4 + 9 + 9+ 16 + 25 = 128
Empirical rule:
- According to this rule almost all the data lies within three standard deviation of the mean for a normal distribution.
- About 68% of data lies within one standard deviation of the mean.
- About 95% of data lies within two standard deviations of mean.
- Arround 99.7% of data lies within three standard deviation of mean.
Thus, by empirical rule,
According to the Empirical Rule, 68% of the data should fall between 11.98 and 18.02
