Solve the system of linear equations using either substitution or the elimination method.

Mathematics

1 answer:

lara31 [8.8K]3 years ago

4 0

Answer:

x = -1

y = 2

Step-by-step explanation:

x + y = 1

y = -x + 1

y = -x + 1 (Multiply this by -1)

y = 3x +5

-y = x - 1

y = 3x +5

0 = 4x + 4

4x = -4

x = -1

x + y = 1

-1 + y = 1

y = 2

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Five students visiting the student health center for a free dental examination during National Dental Hygiene Month were asked h

Andrews [41]

Answer:

[0.9 months, 32.69 months]

Step-by-step explanation:

The mean is

$\bf \bar x=\frac{5+17+12+21+29}{5}=16.8$

The standard deviation is

$\bf s=\sqrt{\frac{(5-16.8)^2+(17-16.8)^2+(12-16.8)^2+(21-16.8)^2+(29-16.8)^2}{5}}=8.1092$

Now, we have to find two values a and b such that the area under the Normal curve with mean 16.8 and standard deviation 8.1092 between a and b equals <em>95% = 0.95 </em>

Using a spreadsheet we find these values are

a = 0.906

b = 32.694

<h3>(See picture) </h3>

and our 95% confidence interval for the mean number of months elapsed since the last visit to a dentist for the population of students participating in the program rounded to two decimal places is

[0.9 months, 32.69 months]