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Nadusha1986 [10]
2 years ago
8

X − y = 12 x + 2y = 21

Mathematics
1 answer:
olga55 [171]2 years ago
5 0

Answer: x=15, y=3

Step-by-step explanation:

Subtracting the two equations, we get -3y=-9, meaning y=3.

Substituting this into the first equation, we get that x-3=12, and thus, x=15.

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Sixty-five randomly selected car salespersons were asked the number of cars they generally sell in one week. Fourteen people ans
ss7ja [257]

Answer:

Step-by-step explanation:

From the information given:

We can compute the required calculations into a table as shown below.

\mathbf{Data \ value  }       \mathbf{ Frequency   } \mathbf{Relative  \ frequency}   \mathbf{Cumulative \  relative }

                                                                                              \mathbf{Frequency}

5                                     14                14/65 = 0.22                           14  

6                                     19                19/65 = 0.29               19+14 = 33

7                                      12                12/65 = 0.19               33+12 = 45

8                                       9                 9/65 = 0.14               45 + 9 = 54

9                                 <u>     11     </u>            11/65  = 0.17              54 + 11 = 65

                                        65

Note: that the relative frequency is determined by  dividing each value in the frequency by the total of the frequency.                        

8 0
2 years ago
Find the midpoint of JK if J(-7. -5) and K(-3,7).
qaws [65]

Answer:

( − 5 , 1 )

Step-by-step explanation:

Use the midpoint formula to find the midpoint of the line segment.

7 0
3 years ago
The ratio of the number of male lions to female lions in the animal reserve is 21:20. If there are 123 lions in the animal reser
Vanyuwa [196]
21 + 20 = 43

Total is 123, so divide by 43.

123/43 = 2.86 rounded to 3.

(females) 20 x 3 = 60 female lions 
7 0
2 years ago
This is my last question by the way
Leni [432]

Part A:

There are 25 blocks for the length, and the length of each is 5.5 inches. 5.5x25=137.5

There are 9 blocks for the height, and each is 2.75 inches. 2.75x9=24.75

Since we're trying to find how much longer the length is to the width, we find the difference. 137.5-24.75=112.75

So part A answer is <em><u>112.75 (or 112¾)</u></em>

Part B:

We know the length is 137.5 and the height is 24.75. To find how many times longer the length is, we need to divide to see how many 24.75 can go into 137.5.

137.5÷24.75=5.55

So the answer to part B is <u><em>5.55. Given the context, the answer would probably be 5, because that's how many entire height can fit.</em></u>

<u><em /></u>

Sorry if it's wrong lol

8 0
3 years ago
95. Because atoms, molecules, and ions are very small, they are counted in units of moles, where 1 mole = 6.022 × 1023 molecules
Galina-37 [17]

Answer:

There are 10⁻⁷ hydrogen ions in one-liter water

Step-by-step explanation:

Hi there!

a. If the pH = 7.0, then:

-log(H) = 7.0

multiply both sides of the equation  by -1

log(H) = -7.0

Apply 10ˣ to both sides

10^(log (H)) = 10⁻⁷

(H) = 10⁻⁷

There are 10⁻⁷ hydrogen ions in one-liter water.

Why 10^(log (H)) = (H)?

Let´s consider this function:

y = 10^(log x)

(Apply log to both sides)

log y = log 10^(log x)

(Apply logarithmic property: log xᵃ = a · log x)

log y = log x · log 10

(log 10 = 1)

log y = log x

y = x

(since y =  10^(log x) and y = x):

10^(log x) = x

That´s why 10^(log (H)) = (H)

7 0
3 years ago
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