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How to find the discriminant of

Evgen [1.6K]

the discriminant b^2 - 4ac when the equation is in the form of ax^2 +bx+c=0

13x^2-16x = x^2 -x

we need to get in it the standard form

subtract x^2 from each side

12x^2 -16x = -x

add x to each side

12x^2 -15x = 0

12x^2 -15x -0 =0

a=12 b=-15 c=0

b^2 -4ac

the discriminant = b^2

b^2 = (-15)2 = 225

6 0

3 years ago

See image attached below keeeeeeeeeeeeeeeeeeeed

emmasim [6.3K]

Answer:

.13%

68.26%

2.28%

47.72%

49.87%

34.13%

Step-by-step explanation:

1.) standardize by subtracting the mean and dividng by the standard deviation

(625-1000)/125= -3

go to a ztable to get .0013 or (1-.9987)

this is equal to .13%

2.)

875<x<1125

standardize both seperately and subtract them

(875-1000)/125= -1 whose probability is .1587 (or 1-.8413)

(1125-1000)/125= 1 whose probability is .8413

.8413-.1587= 68.26%

3.)

Find the probability that someone paid less than 1250 and take its compliment

(1250-1000)/125= 2 which has a probability of .9772

take its compliment (1-.9772)= .0228= 2.28%

4.)

Same process as question 2

(750-1000)/125= -2 which has a probability of (1-.9772) = .0228

(1000-1000)/125= 0 which has a probability of .5

.5-.0228= .4772= 47.72%

5.) same deal as the previous question

(625-1000)/125= -3 which has a probability of (1-.9987)= .0013

(1000-1000)/125= 0 which has a probability of .5

.5-.0013= .4987= 49.87%

6.)same deal the previous question

(875-1000)/125= -1 which has a probability of (1-.8413)=.1587

(1000-1000)/125= 0 which has a probability of .5

.5-.1587= .3413= 34.13%

4 0

3 years ago

Do the rays BA and AB define the same ray? In complete sentences, explain why the two rays are the same or why the two rays are

Deffense [45]

Rays are named according to their endpoints, the first one named is the "starting" endpoint, the second one is the one that will continue on into infinity. Therefore, ray BA has a terminal endpoint at B and goes through point A into infinity. Ray AB has a terminal endpoint at A and goes through point B into infinity. Definitely NOT the same ray.

7 0

3 years ago

Match these items. Match the items in the left column to the items in the right column

Anni [7]

Answer:

sorry I can't solve it like this where is the right column

4 0

3 years ago

The accompanying data on x= head circumference z score (a comparison score with peers of the same age - a positive score suggest

djverab [1.8K]

Answer:

$r=0.77$ , $\hat{y}=770.50+39.37x$ and volume of cerebral brey matter for a child whose head circumference Z score at age 12 months was 1.9 is $\hat {y}=920.10$

Step-by-step explanation:

We attached a table below,

$(a)$ We attached a table below,

Therefore ,

correlation coefficient $r=\frac{\frac{1}{18}(21766.7)-(\frac{27.25}{18} )(\frac{13890}{18} ) }{\sqrt{\frac{1}{18} (59.8435)-(\frac{27.25}{18} )^2}\sqrt{\frac{1}{18}(10767400)-(\frac{13890}{18} )^2 } }$

$=\frac{41.04}{53.19}$

$=0.77$

$(b)$ We calculate the least squares equation.

$b_1=r(\frac{\sigma_y}{\sigma_x} )\\ =(0.77)(\frac{\sqrt{\frac{1}{18} (10767400)-(\frac{13890}{18} )^2} }{\sqrt{\frac{1}{18}(59.8435)-(\frac{27.25}{18} )^2 } } )\\ =0.77(\frac{52.15}{1.02} )\\ =0.77(51.13)\\ =39.37$