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3 years ago

Solve the system using elimination and describe your steps.

Mathematics

2 answers:

Rina8888 [55]3 years ago

7 0

Answer:

x = 2, y = 3

Step-by-step explanation:

3x + y = 9 (1)

5x + 4y = 22 (2)

Multiply equation (1) by -4 and add to equation (2)

-12x - 4y = -36

5x + 4y = 22

-7x = -14

x = 2

Using any equation, solve for y

5(2) + 4y = 22

4y = 12

y = 3

erik [133]3 years ago

3 0

Answer:

x = 2, y=3

Step-by-step explanation:

3x + y = 9

5x + 4y = 22

Multiply the first equation by -4

-4(3x + y) = 9*-4

-12x -4y = -36

Add this to the second equation to eliminate y

-12x -4y = -36

5x + 4y = 22

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

-7x = -14

Divide each side by -7

-7x/-7 = -14/-7

x = 2

Now find y

3x+y = 9

3(2) +y = 9

6+y = 9

Subtract 6 from each side

-6+6 +y = 9-6

y = 3

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a = 15

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3 years ago

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A triangle has sides with lengths of 11 miles, 15 miles, and 17 miles. Is it a right triangle?

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Answer:

Below.

Step-by-step explanation:

If its a right triangle it will obey the Pythagoras theorem.

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3 years ago

A roast turkey is taken from an oven when its temperature has reached 185 degrees F and is placed on a table in a room where the

Vedmedyk [2.9K]

(a) Using Newton's Law of Cooling, $\dfrac{dT}{dt} = k(T - T_s)$ , we have $\dfrac{dT}{dt} = k(T - 75)$ where T is temperature after T minutes.
Separate by dividing both sides by T - 75 to get $\dfrac{dT}{T - 75} = k dt$ . Integrate both sides to get $\ln|T - 75| = kt + C$ .

Since $T(0) = 185$ , we solve for C:
$|185 - 75| = k(0) + C\ \Rightarrow\ C = \ln 110$
So we get $\ln|T - 75| = kt + \ln 110$ . Use T(30) = 150 to solve for k:
$\ln| 150 - 75 | = 30k + \ln 110\ \Rightarrow\ \ln 75 - \ln 110= 30k \Rightarrow \\ k= \frac{1}{30}\ln (75/110) = \frac{1}{30}\ln(15/22)$

So

$\ln|T - 75| = kt + \ln 110 \Rightarrow |T - 75| = e^{kt + \ln110} \Rightarrow \\ \\
|T - 75| = 110e^{kt} \Rightarrow T - 75 = \pm110e^{(1/30)\ln(15/22)t} \Rightarrow \\
T = 75 \pm110e^{(1/30)\ln(15/22)t}$

But choose Positive because T > 75. Temp of turkey can't go under.

$T(t) = 75 + 110e^{(1/30)\ln(15/22)t} \\
T(45) = 75 + 110e^{(1/30)\ln(15/22)(45)} = 136.929 \approx 137{}^{\circ}F$

(b)

$T(t) = 75 + 110e^{(1/30)\ln(15/22)t} = 75 + 110(15/22)^{t/30} \\
100 = 75 + 110(15/22)^{t/30} \\
25 = 110(15/22)^{t/30} 
\frac{25}{110} = (15/22)^{t/30} \\
\ln(25/110) / ln(15/22) = t/30 \\
t = 30\ln(25/110) / ln(15/22) \approx 116\ \mathrm{min}$

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3 years ago

Pedro has a bag of flour that weighs 9/10 pound. he uses 2/3 of the bag to make gravy. how many pounds of flour does pedro use t

BARSIC [14]

Here is the solution of the given problem above.
First, let's analyze the question.
Given: 1 bag = 9/10 pound
2/3 bag = ? pound
What we are going to do is to divide 9/10 pound to 3.
so 9/10 divided by 3 and we get 9/30 and to simplify that, 3/10.
So per 1/3 of the bag, there is 3/10 pound.
To get the weight for 2/3 of the bag, we multiply 3/10 by 2 and we get 6/10 or to simplify it, it is 3/5. Therefore, the 2/3 bag weights 3/5 pound. Hope this answer helps.

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VikaD [51]

Answer:

hope it would help you

Step-by-step explanation:

the ans should be A

mark my ans as BRAIN LIST

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3 years ago

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