All categories

3 years ago

The dimensions of an iPhone are x – 2 and x + 3. If the area of an iPhone is 14 square inches, find the dimensions of the iPhone

Mathematics

1 answer:

QveST [7]3 years ago

3 0

Answer:

The dimensions of the iphone are 2 inches by 7 inches.

Step-by-step explanation:

Given that,

The dimensions of an iPhone are x – 2 and x + 3.

The area of an iphone is 14 sq inches

We need to find the dimensions of the iPhone. It is in the shape of a rectangle. Its area is given by :

$A=l\times b\\\\(x-2)(x+3)=14\\\\x^2-2x+3x-6=14\\\\x^2+x-6-14=0\\\\x^2+x-20=0\\\\x^2+5x-4x-20=0\\\\x(x+5)-4(x+5)=0\\\\(x-4)(x+5)=0\\\\x=4\ and\ x=-5$

Neglecting negative value

First dimension = (x-2) = (4-2) = 2 inches

Other dimension = (x+3) = (4+3) = 7 inches

Hence, the dimensions of the iphone are 2 inches by 7 inches.

You might be interested in

To add or subtract fractions with different denominators, first find equivalent fractions with a _____ denominator.

frosja888 [35]

Common denominator is your answer.

7 0

3 years ago

Read 2 more answers

The population of a country grows exponentially at a rate of 1% per year. If the population was 35.7 million in the year 2010, t

Lady_Fox [76]

Answer:

37.52 million

Step-by-step explanation:

using,

A = A'(1+R/100)ⁿ............................. equation 1

Where A = population size in 2015, A' = Initial population, R = rate in percentage, n = number of times between 2010 and 2015.

Given: A' =35.7 million, R = 1%, n = 5.

Substitute these values into equation 1

A = 35.7(1+0.01)⁵

A = 37.52 million.

Hence the size of the population of the country in the year 2015 is 37.52 million

7 0

3 years ago

Are the solutions correct?

Aloiza [94]

Answer:

First one is wrong. x should be 16.

Second one is not completely visible, so cannot say.

Step-by-step explanation:

In the last step, the divison by 4 yields:

x/16 = 1, so x = 16

4 0

3 years ago

We have a study involving 5 different groups that each contain 9 participants (45 total). What two degrees of freedom would we r

vivado [14]

Answer:

Degree of freedoms F(4,40)

Step-by-step explanation:

Given:

There is a study which is involving 5 different groups that each contains 9 participants (totally 45)

The objective is to calculate the degree of freedoms

Formula used:

Numerator degree of freedom = k-1

denominator degree of freedom=N-K

Solution:

Numerator degree of freedom = k-1

denominator degree of freedom=N-K

Where,

K= number of groups = 5

N= total number of observations

which is given as follows,

N=45

Then,

Numerator degree of freedom = k-1

=5-1

Denominator degree of freedom = N-K

=45-5

=40

Therefore,

Degree of freedoms, F(4,40)

7 0

3 years ago

John, Sally, and Natalie would all like to save some money. John decides that it

brilliants [131]

Answer:

Part 1) John’s situation is modeled by a linear equation (see the explanation)

Part 2) $y=100x+300$

Part 3) $\$12,300$

Part 4) $\$2,700$

Part 5) Is a exponential growth function

Part 6) $A=6,000(1.07)^{t}$

Part 7) $\$11,802.91$

Part 8) $\$6,869.40$

Part 9) Is a exponential growth function

Part 10) $A=5,000(e)^{0.10t}$ or $A=5,000(1.1052)^{t}$

Part 11) $\$13,591.41$

Part 12) $\$6,107.01$

Part 13) Natalie has the most money after 10 years

Part 14) Sally has the most money after 2 years

Step-by-step explanation:

Part 1) What type of equation models John’s situation?

Let

y ----> the total money saved in a jar

x ---> the time in months

The linear equation in slope intercept form

y=mx+b

The slope is equal to

$m=\$100\ per\ month$

The y-intercept or initial value is

$b=\$300$

$y=100x+300$

therefore

John’s situation is modeled by a linear equation

Part 2) Write the model equation for John’s situation

see part 1)

Part 3) How much money will John have after 10 years?

Remember that

1 year is equal to 12 months

$10\ years=10(12)=120 months$

For x=120 months

substitute in the linear equation

$y=100(120)+300=\$12,300$

Part 4) How much money will John have after 2 years?

Remember that

1 year is equal to 12 months

$2\ years=2(12)=24\ months$

For x=24 months

substitute in the linear equation

$y=100(24)+300=\$2,700$

Part 5) What type of exponential model is Sally’s situation?

we know that

The compound interest formula is equal to

$A=P(1+\frac{r}{n})^{nt}$

where

A is the Final Investment Value

P is the Principal amount of money to be invested

r is the rate of interest in decimal

t is Number of Time Periods

n is the number of times interest is compounded per year

in this problem we have

$P=\$6,000\\ r=7\%=0.07\\n=1$

substitute in the formula above

$A=6,000(1+\frac{0.07}{1})^{1*t}\\ A=6,000(1.07)^{t}$

therefore

Is a exponential growth function

Part 6) Write the model equation for Sally’s situation

see the Part 5)

Part 7) How much money will Sally have after 10 years?

For t=10 years

substitute the value of t in the exponential growth function

$A=6,000(1.07)^{10}=\$11,802.91$

Part 8) How much money will Sally have after 2 years?

For t=2 years

substitute the value of t in the exponential growth function

$A=6,000(1.07)^{2}=\$6,869.40$

Part 9) What type of exponential model is Natalie’s situation?

we know that

The formula to calculate continuously compounded interest is equal to

$A=P(e)^{rt}$

where

A is the Final Investment Value

P is the Principal amount of money to be invested

r is the rate of interest in decimal

t is Number of Time Periods

e is the mathematical constant number

we have

$P=\$5,000\\r=10\%=0.10$

substitute in the formula above

$A=5,000(e)^{0.10t}$

Applying property of exponents

$A=5,000(1.1052)^{t}$

therefore

Is a exponential growth function

Part 10) Write the model equation for Natalie’s situation

$A=5,000(e)^{0.10t}$ or $A=5,000(1.1052)^{t}$

see Part 9)

Part 11) How much money will Natalie have after 10 years?

For t=10 years

substitute

$A=5,000(e)^{0.10*10}=\$13,591.41$

Part 12) How much money will Natalie have after 2 years?

For t=2 years

substitute

$A=5,000(e)^{0.10*2}=\$6,107.01$

Part 13) Who will have the most money after 10 years?

Compare the final investment after 10 years of John, Sally, and Natalie

Natalie has the most money after 10 years

Part 14) Who will have the most money after 2 years?

Compare the final investment after 2 years of John, Sally, and Natalie

Sally has the most money after 2 years

3 0

3 years ago