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3 years ago

If f(x)=2x+5, then what is f(3)?

Mathematics

2 answers:

FromTheMoon [43]3 years ago

7 0

Answer:

$\Large \boxed{f(3)=11}$

Step-by-step explanation:

$f(x)=2x+5$

For f(3), the input for the function f(x) is 3.

Let x (input) = 3.

$f(3)=2(3)+5 \\\\ f(3)=6+5 \\\\ f(3)=11$

Marta_Voda [28]3 years ago

5 0

Answer:

Step-by-step explanation:

f(x)=2x+5

Let x = 3

f(3) = 2*3+5

= 6+5

= 11

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Nicole bought a $3,200 computer on the installment plan. She made a $300 down payment, and

marishachu [46]

Answer:

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Step-by-step explanation:

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3 years ago

Find the output y when the input x is -5<br> y=?

antiseptic1488 [7]

Answer: y=7

Step-by-step explanation: looking at the graph when x is -5 y= 7

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3 years ago

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2 years ago

Select the equation in point-slope form for the line that passes through the point (1, –1) and has a slope of 4.

Dvinal [7]

Answer:

$\large \boxed{y + 1 = 4(x - 1)}$

Step-by-step explanation:

The point-slope formula for a straight line is

y - y₁= m(x - x₁)

x₁ = 1; y₁ = -1; m = 4

Substitute the values

$\begin{array}{rcl}y - (-1) & = & 4(x - 1)\\y + 1 & = & 4(x - 1)\\\end{array}\\\text{The equation for the line in point-slope form is $\large \boxed{\mathbf{y + 1 = 4(x - 1)}}$}$

The figure shows the graph of the equation with slope 4 passing through (1, -1).

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3 years ago

A rectangular garden of area 480 square feet is to be surrounded on three sides by a brick wall costing $ 12 per foot and on one

seraphim [82]

Answer:

Therefore the dimensions of the rectangular garden are 23.42 ft by 20.5 ft.

Step-by-step explanation:

Given that,

A rectangular garden of area 480 square feet.

Let length of the rectangular garden be x which is surrounded by fence and width of the rectangular garden be y.

Then xy is the area of the given rectangular garden .

Then,

xy= 480

$\Rightarrow y=\frac{480}{x}$

The length of the tree sides which are surrounded by brick wall is = 2y+x.

The cost for the brick wall is =Length×cost per feet= $12(2y+x)

The cost for the fencing is =Length×cost per feet= $ 9x

$\therefore C=12(2y+x)+9x$

Now putting $y=\frac{480}{x}$

$\therefore C=12(2.\frac{480}{x}+x)+9x$

$\Rightarrow C=\frac{11520}{x}+21x$

Differentiating with respect to x

$C'=-\frac{11520}{x^2}+21$

Again differentiating with respect to x

$C''=\frac{23040}{x^3}$

Now we set C'=0

$\therefore-\frac{11520}{x^2}+21=0$

$\Rightarrow\frac{11520}{x^2}=21$

$\Rightarrow x^2=\frac{11520}{21}$

$\Rightarrow x\approx 23.42$

$C''|_{x=23.42}=\frac{23040}{(23.42)^3}>0$ .

Since at x=23.42,C''>0. So at x=23.42, the total cost will be minimum.

The width of the rectangular garden is $y=\frac{480}{x}$

$=\frac{480}{23.42}$

$\approx 20.5$

Therefore the dimensions of the rectangular garden are 23.42 ft by 20.5 ft.

The cost of the material is $C=\frac{11520}{x}+21x$

$=\frac{11520}{23.42}+21\times 23.42$

=$983.70

5 0

3 years ago