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kap26 [50]
3 years ago
5

All questions to be solved using linear combination.

Mathematics
1 answer:
monitta3 years ago
8 0
1)
I:x-y=-7
II:x+y=7

add both equations together to eliminate y:
x-y+(x+y)=-7+7
2x=0
x=0

insert x=0 into II:
0+y=7
y=7

the solution is (0,7)

2)
I: 3x+y=4
II: 2x+y=5

add I+(-1*II) together to eliminate y:
3x+y+(-2x-y)=4+(-5)
x=-1

insert x=-1 into I:
3*-1+y=4
y=7

the solution is (-1,7)

3)

I: 2e-3f=-9
II: e+3f=18

add both equations together to eliminate f:
2e-3f+(e+3f)=-9+18
3e=9
e=3

insert e=3 into I:
2*3-3f=-9
-3f=-9-6
-3f=-15
3f=15
f=5

the solution is (3,5)

4)
I: 3d-e=7
II: d+e=5

add both equations together to eliminate e:
3d-e+(d+e)=7+5
4d=12
d=3

insert d=3 into II:
3+e=5
e=2

the solution is (3,2)

5)
I: 8x+y=14
II: 3x+y=4

add I+(-1*II) together to eliminate y
8x+y+(-3x-y)=14-4
5x=10
x=2

insert x=2 into II:
3*2+y=4
y=4-6
y=-2

the solution is (2,-2)
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Work backwards from your instructions

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A coffee company wants to make sure that their coffee is being served at the right temperature. If it is too hot, the customers
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Answer:

Null hypothesis:\mu = 65  

Alternative hypothesis:\mu \neq 65

t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}  (1)  

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".  

For this case the value of \mu represent the parameter associated to the population (True average of cofee temperature)

Step-by-step explanation:

Data given and notation  

\bar X=70.2 represent the mean height for the sample  

s represent the sample standard deviation for the sample  

n=20 sample size  

\mu_o =765 represent the value that we want to test

\alpha represent the significance level for the hypothesis test.  

t would represent the statistic (variable of interest)  

p_v represent the p value for the test (variable of interest)  

State the null and alternative hypotheses.  

We need to conduct a hypothesis in order to check if the true mean i equal to 70.2, the system of hypothesis would be:  

Null hypothesis:\mu = 65  

Alternative hypothesis:\mu \neq 65  

If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:  

t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}  (1)  

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".  

For this case the value of \mu represent the parameter associated to the population (True average of cofee temperature)

3 0
3 years ago
A rectangle has length 4 yards more than its width. The area of the rectangle is 96 square yards. Find the
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Answer:

Length = 12

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Step-by-step explanation:

Area of a Rectangle = l x w

12 x 8 = 96

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Answer:

Step-by-step explanation:

jjefhiuewubgiurbvrebf

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In 3 metres there are 300 centimetres. Each centimetre on the scale is 300 centimeters, or a ratio of 1:300. The tree is 5 centimetres on the scale. Each centimeter on the scale is 300 centimetres, therefore 5 centimetres on the scale is 1500 centimetres. 1500 centimetres is equal to 15 metres.
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