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1 year ago

14

Type the correct answer in the box. Jason builds doghouses for a pet store. Each doghouse is a wooden structure with a rectangul

ar base that has an area of 21 square feet and a length that is 4 feet more than its width. If x represents the width of the doghouse, write an equation in the given form that can be used to determine the possible dimensions of the base of the doghouse. 

2 answers:

Basile [38]1 year ago

8 0

Answer:

Width = 3 feet

Length = 7 feet

Step-by-step explanation:

x represents the width of doghouse so,

Width = x

Length is 4 times more than its width

Length = x+4

Area of doghouse = 21 square feet

We know

Area of rectangle = Length * Width

21 = (x+4)*x

21 = x^2+4x

=> x^2+4x-21=0

Solving the above quadratic equation by factorization to find the value of x

x^2+7x-3x-21=0

x(x+7)-3(x+7)=0

(x+7)(x-3)=0

x+7 =0 and x-3=0

x= -7 and x =3

Since the width of rectangle can never be negative so, x=3

Width =x = 3 feet

Length = x+4 = 3+4 = 7 feet

WINSTONCH [101]1 year ago

6 0

Answer: (x + 7)(x - 3) = 0

width (x) = 3

length (x+4) = 7

<u>Step-by-step explanation:</u>

Area (A) = length (l) × width (x)

21 = (x + 4) × (x)

21 = x² + 4x <em>distributed (x) into (x + 4)</em>

0 = x² + 4x - 21 <em>subtracted 21 from both sides</em>

0 = (x + 7)(x - 3) <em>factored quadratic equation</em>

0 = x + 7 or 0 = x - 3 <em>applied Zero Product Property</em>

x = -7 or x = 3 <em>solved each equation</em>

x = -7 is not valid <em>because lengths cannot be negative </em>

so x = 3

and length ... x + 4 = (3) + 4 = 7

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$\bar x = 1.3538$

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Both conditions are equivalent on this case. We can use the z score again in order to find the value a.

As we can see on the figure attached the z value that satisfy the condition with 0.9 of the area on the left and 0.1 of the area on the right it's z=1.28. On this case P(Z<1.28)=0.9 and P(z>1.28)=0.1

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Step-by-step explanation:

Data given:

0.86 0.88 0.88 1.07 1.09 1.17 1.29 1.31 1.46 1.49 1.59 1.62 1.65 1.71 1.76 1.83

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We can calculate the mean with the following formula:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

And for this case if we use this formula we got:

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For this case in order to calculate the median we need to put the data on increasing way like this:

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And replacing we got:

$Var(\frac{x_{8} +x_{9}}{2})= \frac{0.3105^2}{2}= 0.0482$

And the standard error would be given by:

$Sd(\frac{x_{8} +x_{9}}{2})= \sqrt{0.0482}=0.2196$

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