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3 years ago

3x+7=13 (x=-2;x=2;x=5)

Mathematics

2 answers:

AnnZ [28]3 years ago

5 0

X=2 because 3 times 2 is 6 and then you add 6 and 7 together and get 13.

IgorLugansk [536]3 years ago

3 0

Answer: x=2

Step-by-step explanation:

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The function f(x) = { x + 1 is used to complete this Which statements are true of the given function? Check all that apply. tabl

Dmitry [639]

Answer:

Options (1) and (5)

Step-by-step explanation:

Expression that defines the function is,

$f(x)=\frac{1}{2}x+\frac{3}{2}$

Option 1

$f(-\frac{1}{2})=\frac{1}{2}(-\frac{1}{2})+\frac{3}{2}$

$=-\frac{1}{4}+\frac{3}{2}$

$=-\frac{1}{4}+1+\frac{1}{2}$

$=1+\frac{1}{4}$

$=1\frac{1}{4}$

So, $f(-\frac{1}{2} )=-2$ is false.

Option 2

f(0) = $\frac{1}{2}(0)+\frac{3}{2}$

= $\frac{3}{2}$

True.

Option 3

f(1) = $\frac{1}{2}(1)+\frac{3}{2}$

= $\frac{3+1}{2}$

= 2

Therefore, f(1) = -1 is false.

Option 4

$f(2)=\frac{1}{2}(2)+\frac{3}{2}$

$=1+1+\frac{1}{2}$

$=2\frac{1}{2}$

Therefore, f(2) = 1 is false.

Option 5

f(4) $=\frac{1}{2}(4)+\frac{3}{2}$

$=2+\frac{3}{2}$

$=\frac{4+3}{2}$

$=\frac{7}{2}$

True.

Options (1) and (5) are the correct options.

5 0

3 years ago

Jack was out at a restaurant for dinner when the bill came. His dinner came to $14. He wanted to leave a 31% tip. How much was h

inessss [21]

Answer:

$18.34

Step-by-step explanation:

8 0

2 years ago

Read 2 more answers

Please help with all of these!!

bija089 [108]

I can't see it clearly the questions ?

5 0

3 years ago

Which number is the square root of 196

Elodia [21]

Hi there,

I think the answer is

14

Have a nice day

8 0

3 years ago

A fence must be built to enclose a rectangular area of 20,000 ft^2. Fencing material costs $4 per foot for the two sides facing

Marysya12 [62]

The cost of the least expensive fence is $3200

Step-by-step explanation:

The given is:

A fence must be built to enclose a rectangular area of 20,000 ft²
Fencing material costs $4 per foot for the two sides facing north and south and $8 per foot for the other two sides

We need to find the cost of the least expensive fence

Assume that the length of each side opposite to North or South is x feet and the length of each other sides is y feet

∵ The length of the rectangle = x feet

∵ The width of the rectangle = y feet

∵ The rectangular area is 20,000 ft²

- Area of a rectangle = length × width

∴ x × y = 20,000

- Divide both sides by x to find y in terms of x

∴ $y=\frac{20,000}{x}$

The fence's length is equal to the perimeter of the rectangular area

∵ Perimeter of the rectangle = 2 length + 2 width

∴ Perimeter of the rectangle = 2x + 2y

∵ Fencing material costs $4 per foot for the two sides facing

North and South

∴ x costs $4 per foot

∵ The cost of the other two sides is $8 per foot

∴ y costs $8 per feet

The cost of the fence is the sum of the products of 4 , 2x and 8 , 2y

∵ The cost of the fence (C) = 4(2x) + 8(2y)

∴ C = 8x + 16y

- Substitute y by its value above

∴ $C=8x+16(\frac{20,000}{x})$

∴ $C=8x+\frac{320,000}{x}$

To find the least expensive differentiate C with respect to x and equate the answer by 0 to find the value of x

∵ $\frac{320,000}{x}$ can be written as $320,000x^{-1}$

∴ $C=8x+320,000x^{-1}$

∵ $\frac{dC}{dx}=8(1)x^{1-1}+320,000(-1)x^{-1-1}$

∴ $\frac{dC}{dx}=8-320,000x^{-2}$

- Equate $\frac{dC}{dx}$ by zero

∴ $8-320,000x^{-2}=0$

∵ $-320,000x^{-2}=-\frac{320,000}{x^{2}}$

∴ $8-\frac{320,000}{x^{2}}=0$

- Subtract 8 from both sides

∴ $-\frac{320,000}{x^{2}}=-8$

- Multiply both sides by x²

∴ - 320,000 = - 8x²

- Divide both sides by -8

∴ 40,000 = x²

- Take √ for both sides

∴ 200 = x

Substitute x in the equation of C to find the least cost of fence

∵ $C=8(200)+\frac{320,000}{(200)}$

∴ C = 1600 + 1600

∴ C = 3200

The cost of the least expensive fence is $3200

Learn more:

You can learn more about the differentiation in brainly.com/question/4279146

#LearnwithBrainly

5 0

3 years ago