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3 years ago

Solving systems equations by elimination

1 answer:

3 0

I won't answer them all for you (don't want to cheat - need to learn something).
But for the first one given:

<span>-2x-9y=-25
-4x-9y=-23

you set up either x or y (which ever one you want to eliminate) so that one of them cancels.
So this one is easy - you just have to multiply an entire row by negative (doesn't matter which one) - so that the y's will be + and -

Since they're both 9 and they're subracting NOW - you can eliminate the y value. Now add/subtract the x's. So it'd be -2 or 2 depending on how you eliminated y. Then add the number outside of the = sign. Now just solve for x. After that plug in whatever you got for x into both of the rows. Then find the y value.

Hopefully this wasn't confusing -- reply if it is and I will try to simplify. I can give you contact if you need help with the rest

Good luck!</span>

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It has been hypothesized that the standard deviation of the germination time of radish seeds is 8 days. The standard deviation o

Yanka [14]

Answer:

$\chi^2 =\frac{60-1}{64} 36 =33.19$

The degrees of freedom are:

$df= n-1= 60-1= 59$

And the p value would be given by:

$p_v =2*P(\chi^2 >33.19)=0.0053$

Since the p value is lower than the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true deviation is different from 8 days.

Step-by-step explanation:

Data given

$n=60$ represent the sample size

$\alpha=0.01$ represent the confidence level

$s^2 =6^2 =36$ represent the sample variance obtained

$\sigma^2_0 =8^=64$ represent the value that we want to test

Hypothesis to test

We want to verify if the true deviation is equal to 8 days o not, so the system of hypothesis would be:

Null Hypothesis: $\sigma^2 = 64$

Alternative hypothesis: $\sigma^2 \neq 64$

The statistic is given by:

$\chi^2 =\frac{n-1}{\sigma^2_0} s^2$

Replacing we got:

$\chi^2 =\frac{60-1}{64} 36 =33.19$

The degrees of freedom are:

$df= n-1= 60-1= 59$

And the p value would be given by:

$p_v =2*P(\chi^2 >33.19)=0.0053$

Since the p value is lower than the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true deviation is different from 8 days.

6 0

3 years ago

Surya is competing in a triathlon that includes swimming, bicycling and running. For the first two segments of the race, Surya s

kirill115 [55]

Hehshdndnzjxjbshzhsbsbsbsbzjzjn 29

8 0

3 years ago

Read 2 more answers

Point A is (-9,-3) and is translated 4 left and 2 down. Where is A' at?

mezya [45]

Answer:

A translation maps point A(3,7)A(3,7)A, left parenthesis, 3, comma, 7, right parenthesis to point A'(6,-2)A

′

(6,−2)A, prime, left parenthesis, 6, comma, minus, 2, right parenthesis. Let's determine what translation this is.

Solution

Step 1: Horizontal shift. AAA is shifted 333 units to the right because (6)-(3)=\tealD{+3}(6)−(3)=+3left parenthesis, 6, right parenthesis, minus, left parenthesis, 3, right parenthesis, equals, start color #01a995, plus, 3, end color #01a995.

Step 2: Vertical shift. AAA is shifted 999 units down because (-2)-(7)=\maroonD{-9}(−2)−(7)=−9left parenthesis, minus, 2, right parenthesis, minus, left parenthesis, 7, right parenthesis, equals, start color #ca337c, minus, 9, end color #ca337c.

The answer: AAA is mapped onto A'A

′

A, prime under a translation by \langle \tealD{3},\maroonD{-9} \rangle⟨3,−9⟩open angle, start color #01a995, 3, end color #01a995, comma, start color #ca337c, minus, 9, end color #ca337c, close angle.

Step-by-step explanation:

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3 years ago

A survey of a group of seventh graders and a group of teachers at a local middle school asked how many siblings they each have.

nevsk [136]

Answer:

where is the other dot plot

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3 years ago

How many quarts are in 9 gallons?

kati45 [8]

Answer:

1 gallon = 4 quarts

4 × 9 = 36

36 quarts are in 9 gallons

4 0

2 years ago