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3 years ago

Can I get help on this problem showing my work?

Mathematics

2 answers:

Evgen [1.6K]3 years ago

6 0

$cost \: of \: 1 \:bracelet \\(no\:shipping): \\72 \: dollars - 9 \: dollars \: shipping = \\ 63 \: \div 9 \: = cost \: of \: 1 \: bracelet \: \\ = 7 \: dollars$
$\\cost \: of \: shipping: \\ 9 \: dollars \: \div 9 \: bracelets \: = \\ 1 \: dollar\: per\:bracelet \\ \\ formula \: for \: cost \: overall: \\ 7y \: + y$

y = quantity, for example:

I want to buy 1 bracelet =
1×7 = 7 + 1 = 8$ per bracelet

Anon25 [30]3 years ago

4 0

9x+9+72

9x= total cost

9= shipping fee

72= what you paid in all

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I need help with 5&6 please ASAP!!!!!!!

Elenna [48]

Hi BFFF IM MDJXJCNDM

4 0

3 years ago

Read 2 more answers

Newton's law of cooling is:

Mnenie [13.5K]

Answer:

$t = \frac{ln(\frac{21}{59})}{-0.15}=6.887 hr$

So it would takes approximately 6.9 hours to reach 32 F.

Step-by-step explanation:

For this case we have the following differential equationÑ

$\frac{du}{dt}= -k (u-T)$

We can reorder the expression like this:

$\frac{du}{u-T} = -k dt$

We can use the substitution $w = u-T$ and $dw =du$ so then we have:

$\frac{dw}{w} =-k dt$

IF we integrate both sides we got:

$ln |w| = -kt +C$

If we apply exponential in both sides we got:

$w = e^{-kt} *e^c$

And if we replace w = u-T we got:

$u(t)= T + C_1 e^{-kt}$

We can also express the solution in the following terms:

$u(t) = (T_i -T_{amb}) e^{kt} +T_{amb}$

For this case we know that $k =-0.15 hr$ since w ehave a cooloing, $T_{i}= 70 F, T_{amb}=11F$ , we have this model:

$u(t) = (70-11) e^{-0.15t} +11$

And if we want that the temperature would be 32F we can solve for t like this:

$32 = 59 e^{-0.15 t} +11$

$21=59 e^{-0.15 t}$

$\frac{21}{59} = e^{-0.15 t}$

If we apply natural logs on both sides we got:

$ln (\frac{21}{59}) =-0.15 t$

$t = \frac{ln(\frac{21}{59})}{-0.15}=6.887 hr$

So it would takes approximately 6.9 hours to reach 32 F.

7 0

3 years ago

Total mass vs. numbers of cd and numbers of cd

Gekata [30.6K]

Answer: Choice A) M = 0.25n + 100

=============================================================

Explanation:

For now, I'll treat n as x, and M as y.

In other words,

x = number of CDs
y = total mass in kg

Let's select two points from this graph. I'll pick (200,150) and (400,200)

The slope of the line through those points is

m = (y2-y1)/(x2-x1)

m = (200-150)/(400-200)

m = 50/200

m = 0.25

Now we'll use the point (x,y) = (200,150) along with that slope value to find the y intercept b

y = mx+b

150 = 0.25*200+b

150 = 50+b

150-50 = b

100 = b

b = 100

You could also use (x,y) = (400,200) and you should get the same b value.

In fact, any other point from this graph works as well.

------------------------------

Since m = 0.25 and b = 100, we go from y = mx+b to y = 0.25x+100

This then translates over to M = 0.25n + 100 which is choice A

To help verify this, let's say we plugged in n = 100

M = 0.25*n + 100

M = 0.25*100 + 100

M = 25 + 100

M = 125

Which is confirmed by what the graph shows. I'll let you check the other points as well.

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3 years ago

I really need this answered. I need to find the area

kipiarov [429]

Answer:

I think 5

Step-by-step explanation:

5 0

3 years ago

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2 * 2 * 4 * 5 * 6 * 2 * 2 * 5 * 7 * 5 = ? will mark brainliest!

BaLLatris [955]

Answer:

336,000

Step-by-step explanation:

2 × 2 = 4 x 4 = 16 × 5 = 80 × 6 = 480 x 2 = 960 x 2 = 1920 × 5 = 9600 x 7 = 62700 × 5 = 336,000

3 0

2 years ago