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3 years ago

Guys help

Mathematics

2 answers:

RideAnS [48]3 years ago

8 0

Step-by-step explanation:

(-23) x 93 = - 2139

(- 16 ) x (- 30) = 480

14 x (- 12) = - 168

Inessa [10]3 years ago

8 0

2139
thats for the first question

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The liquid base of an ice cream has an initial temperature of 86°C before it is placed in a freezer with a constant temperature

Karolina [17]

The temperature of the ice cream 2 hours after it was placed in the freezer is 37.40 °C

From Newton's law of cooling, we have that

$T_{(t)}= T_{s}+(T_{0} - T_{s})e^{kt}$

Where

$(t) = \ time$

$T_{(t)} = \ the \ temperature \ of \ the \ body \ at \ time \ (t)$

$T_{s} = Surrounding \ temperature$

$T_{0} = Initial \ temperature \ of \ the \ body$

$k = constant$

From the question,

$T_{0} = 86 ^{o}C$

$T_{s} = -20 ^{o}C$

∴ $T_{0} - T_{s} = 86^{o}C - -20^{o}C = 86^{o}C +20^{o}C$

$T_{0} - T_{s} = 106^{o} C$

Therefore, the equation $T_{(t)}= T_{s}+(T_{0} - T_{s})e^{kt}$ becomes

$T_{(t)}=-20+106 e^{kt}$

Also, from the question

After 1 hour, the temperature of the ice-cream base has decreased to 58°C.

That is,

At time $t = 1 \ hour$ , $T_{(t)} = 58^{o}C$

Then, we can write that

$T_{(1)}=58 = -20+106 e^{k(1)}$

Then, we get

$58 = -20+106 e^{k(1)}$

Now, solve for $k$

First collect like terms

$58 +20 = 106 e^{k}$

$78 =106 e^{k}$

Then,

$e^{k} = \frac{78}{106}$

$e^{k} = 0.735849$

Now, take the natural log of both sides

$ln(e^{k}) =ln( 0.735849)$

$k = -0.30673$

This is the value of the constant $k$

Now, for the temperature of the ice cream 2 hours after it was placed in the freezer, that is, at $t = 2 \ hours$

From

$T_{(t)}=-20+106 e^{kt}$

Then

$T_{(2)}=-20+106 e^{(-0.30673 \times 2)}$

$T_{(2)}=-20+106 e^{-0.61346}$

$T_{(2)}=-20+106\times 0.5414741237$

$T_{(2)}=-20+57.396257$

$T_{(2)}=37.396257 \ ^{o}C$

$T_{(2)} \approxeq 37.40 \ ^{o}C$

Hence, the temperature of the ice cream 2 hours after it was placed in the freezer is 37.40 °C

Learn more here: brainly.com/question/11689670

6 0

2 years ago

Read 2 more answers

PLEASEEE HELP BIG FINALS TEST !!!! :( plssssss

Sati [7]

I’m pretty sure I know the answers but could you tell me the options for the drop boxes:)

7 0

2 years ago

Find 4 consecutive even integers such that when three times the smallest of the intagers is added to twice the largest their sum

zhannawk [14.2K]

If x is the first of the integers then the statement is:

(x) , (x+2) , (x+4) , (x+6)

This means that the smallest is x and the largest is x + 6

so:
3(x) + 2(x+6) = 293
3x + 2x + 12 = 293
5x = 281
x = 56.2
This gives us a none integer (decimal)
What now?

Wait remember how x started as the lowest? what if x was the highest instead?

x, x-2, x-4, x-6
so:

3(x-6) + 2(x) = 293
5x = 315
x = 62.2

This is as close as have gotten to the answer
Cant seem to get an integer.
Maybe error in the question or some bad math on my part.

3 0

3 years ago

Teenage Mutant Ninja Turtles desmos

grigory [225]

Answer:

i agree

Step-by-step explanation:

5 0

2 years ago

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Helps, also explain how to do it I want to learn how and stop using brainy

Nutka1998 [239]

Answer:

259

Step-by-step explanation:

USE PEMDAS

Parenthesis

Exponent

Multiplication

Division

Addition

Subtraction

5 0

3 years ago