3. Use proportional reasoning to answer the following question.
When buying an item, discount is always taken off
before applying tax. How much does a $1200
phone cost with a 35% discount and 10% tax?

well, first off, when it comes to volumes by rotation, we'd want to graph them, Check the picture below.  Our rotation over the axis will give us a "washer", so we'll be using the washer method.

now, our axis of rotation is the y-axis or namely x = 0, x = 0 is a vertical line, meaning we have to put the functions in y-terms, that is in f(y) form

[tex]y = x^2\implies \pm\sqrt{y}=x\implies \boxed{\pm\sqrt{y}=f(y)} \\\\\\ y = 4x\implies \cfrac{y}{4}=x\implies \boxed{\cfrac{y}{4}=g(y)}[/tex]

if we look at the picture, the parabola is the farthest from the axis of rotation and the line is the closest, or namely R² and r² respectively.

the way I get the area for R² and r², is by using the same I do with "area under the curve", so if I say call the axis of rotation h(y), the way I get the area is

R => f(y) - h(y)

r => g(y) - h(y)

so let's proceed.

[tex]\textit{area under the curve}\\ \begin{array}{llll} \sqrt{y}- 0\implies &\sqrt{y}\\ \frac{y}{4}-0\implies &\frac{y}{4} \end{array}\qquad \qquad \begin{array}{llll} \stackrel{R^2}{(\sqrt{y})^2}-\stackrel{r^2}{\left( \frac{y}{4} \right)^2}\\[-0.5em] \hrulefill\\ y\qquad -\qquad \frac{y^2}{16} \end{array}[/tex]

now, we want to get the area enclosed by both, and thus we'd need their points of intersection, setting both to [tex]\sqrt{y}=\cfrac{y}{4}[/tex]  which in short gives us the bounds of 0 and 16.

[tex]\pi \displaystyle\int_{0}^{16}\left( y - \cfrac{y^2}{16} \right)dy\implies \pi \int_{0}^{16}y\cdot dy-\pi \int_{0}^{16}\cfrac{y^2}{16}\cdot dy\\\\\\\pi \cdot \left. \cfrac{y^2}{2} \right]_{0}^{16}-\pi \cdot \left. \cfrac{y^3}{48} \right]_{0}^{16}\implies 128\pi -\cfrac{256\pi }{3}\implies \boxed{\cfrac{128\pi }{3}}[/tex]

Answer:

D

Step-by-step explanation:

F(g) falls between 0 and 49.58

Answer:

just see how many times 3 goes into 80 which is 26. so then that leaves you with 5 and 3 goes into 5 only 1 time so the answer is 26 and 2

Answer:

[tex]\huge \bf༆ Answer ༄[/tex]

Let's solve ~

you can further simplify to get ~

1

Step-by-step explanation:

true ya false you say me

Answer:

Ok

Step-by-step explanation:

Answer:

327

Step-by-step explanation:

Answer:

The empty space in the equation doesn't make sense. We could answer this question if it gave us the sum and we solved for x. But, for the sake of the question let's get rid of the periods. The question would now be 35 + 36 + 37 + 38 + 109 + 110. When we solved the equation we would get 365.

Step-by-step explanation:

Answer:

multiply

16

Step-by-step explanation:

yeah-ya....... right?

Answer:

Step-by-step explanation:

Answer: C

Step-by-step explanation:

Answer:

The Answer Is B

Step-by-step explanation:

Answer:

x= 5 or x= -5

Step-by-step explanation:

[tex] \frac{x + 4}{3} = \frac{3}{x - 4} [/tex]

Cross multiply:

(x +4)(x -4)= 3(3)

Expand:

[tex]\boxed{a {}^{2} - {b}^{2} = (a + b)(a - b)}[/tex]

x² -4²= 9

x² -16= 9

+16 on both sides:

x²= 9 +16

x²= 25

Square root both sides:

[tex]x = ± \sqrt{25} [/tex]

x= 5 or x= -5

Given that:

[(x+4)/3] = [3/(x-4)]

We know that

(a/b) = (c/d)

⇛a(d) = b(c)

Now,

By using cross multiplying fraction, we get

⇛x+4(x-4) = 3(3)

⇛x(x-4) + 4(x-4) = 9

⇛x² - 4x + 4x - 16 = 9

⇛x² - 0 -16 = 9

⇛x² = 9+16

⇛x² = 25

⇛x = √(25)

⇛x = ±√(5*5)

⇛x = ±5 = +5 or -5 Ans.

also read similar questions: Solve the expression and find the value of x. [tex] \frac{x⁠…

https://brainly.com/question/25420312

Can some one help me solve this x+3/2+3x/7 = 7

https://brainly.com/question/25742683

Answer:

See below

Step-by-step explanation:

Dilation of 4

Z (0, -1) Z' (0, -4)

X (1, -1) X' (4, -4)

Answer:

look it up in internet and find th right answers

Answer:

g(x)=3|x| is the first box

f(x)=1/3|x| is the second box

Step-by-step explanation:

you can solve these type of questions by looking at the slope which is in front of the x.

since 1/3 is smaller than 3 it's going to have lower slope resulting in 3 to incline faster

Answer:

Step-by-step explanation:

Let the number is x.

Translate the given into equation and solve for x:

Answer:

克拉克夫人的植物高 4/3 4 英寸。它比吉米的植物高 1/7 8 英寸。何

Step-by-step explanation:

the scale factor is 1 : 150

you don't know what that means ?

it means that every unit (here cm) in the diagram corresponds in reality to 150 units.

so, 1 cm in the diagram is 150 cm in reality.

therefore we only need to multiply the sizes in the diagram by 150, and we get the real sizes.

length : 5 × 150 = 750 cm (7.5 m)

breadth : 3 × 150 = 450 cm (4.5 m)

and the perimeter is as for every rectangle :

2×length + 2×breadth = 2×750 + 2×450 = 1500 + 900 =

= 2400 cm (24 m)

Step-by-step explanation:

We can prove KK'M and LL'M are congruent by using ASA (Angle side angle). Angle side angle means that if we know two angles and one side, we can prove that they are congruent.

First, we know that ∠KMK' = ∠LML' because they are alternative angles. (That's our fist A)

Next, The problem states that KK' and LL' are equal. (so that gives our S)

Finally, we know that ∠ML'L and ∠KK'M are both 90 degrees, making them both equal. (That's our final A)

Hope this helped :D

2b + 21 < 22

b is the unknown number so multiply it by 2 to get 2b then add 21, bring the less than sign and write the 22 after the less than sign

Answer:

It's be 60 because 30% of 60 is 18. Hope that helped :)

okay. first you must get the properties of a triangle. all three angles are 180 degrees in total. the angle of a straight line is also 180 degrees. both the triangle and the straight line shares the same angle ACB. so you can conclude that 5x-35 = 2x+58

-2x from both sides and 3x-35= 58

so 3x = 58+ 35= 93

x= 31

ABC = 31x2 = 62

BCA = 180-58-62= 60 degrees

please give me brailiest . thanks!

Answer:

x =31°

ABC is 62°

BCA IS 60°

I HOPE THIS IS HELPING

Answer:

8, 2.

Step-by-step explanation:

2*4 is 8 so I think line them up together and 12/6 is 2

Answer:

$20,000

Step-by-step explanation:

20,000 / 0.07 = 1400

Answer:

The correct answers are:

B

D and

F

Step-by-step explanation:

Hope it can help you lovelots

#LEARN WITH BRAINLY

[tex]8(6x-7)<5(9x-4)\\\\\implies 48x- 56<45x -20\\\\\implies 48x-45x -56<-20\\\\\implies 3x < -20 +56\\\\\implies 3x<36\\\\\implies x < \dfrac{36}3\\\\\implies x<12\\\\\text{Interval,}~ (-\infty,12)[/tex]

Answer:

w = 5

Step-by-step explanation:

Step 1: Use the Distributive property to get 6w + 30.

Step 2: Divide 6w by 6 and cancel out both 6s.

Step 3: Divide 30 by 6 to get 5, and you have the answer.

Answer:

Correct answer: 2.25

Answer:

Below in bold.

Step-by-step explanation:

0.3. e^3x = 27

Taking logs of both sides:

ln (0.3. e^3x) = ln 27

ln (0.3) + ln e^3x = ln 27

ln e^3x = ln 27 - ln(0.3)

3x = ln 27 - ln 0.3

3x = ln(27/0.3) = ln 90

x = 1/3 ln 90

x = ln (90^1/3)

Approximate value of x:

= 1.499936557

= 1.500 to the nearest thousandth.

Step-by-step explanation:

x-8/2 = x-5/5

5(x-8) = 2(x-5)

5x-40 = 2x-10

3x= 30

x = 10

Answer:

x = 10

Step-by-step explanation:

[tex]\frac{x-8}{2}[/tex] = [tex]\frac{x-5}{5}[/tex] ( cross- multiply )

5(x - 8) = 2(x - 5) ← distribute parenthesis on both sides

5x - 40 = 2x - 10 ( subtract 2x from both sides )

3x - 40 = - 10 ( add 40 to both sides )

3x = 30 ( divide both sides by 3 )

x = 10