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lozanna [386]
2 years ago
15

If 2x – 10y = -1 and 5x + 6y = 4 are true equations, what would be the value of 7x - 4y?

Mathematics
1 answer:
Zigmanuir [339]2 years ago
8 0

Answer:

Step-by-step explanation:

If the equations are true, they can be solved simultaneously.

Consider 2x-10y=-1 as Eq1 and 5x+6y=4 as Eq2

Multiplying Eq1 with 3 and Eq2 with 5 we get,

6x-30y=-3 -- Eq3 and 25x+30y=20 -- Eq4

Adding Eq3 and Eq4,

31x=17 Therefore, x=17/31

Plugin x=17/31 in Eq3,

6(17/31)-30y=-3 --- y=13/62

Plug In values of x and y in 7x-4y we get,

7(17/31)-4(13/62) = 3

So the value of 7x-4y = 3.

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5(2+c)=45+5c no solution​
kolbaska11 [484]

Answer:

Step-by-step explanation:

You have to start out with the distributive property 5 times 2 times c is 10+5c; now you have to subtract 5c on both sides in the upside down T chart, now its 10=45+c and your answer will be c=4.5.

8 0
3 years ago
The vertex of this parabola is at (-3, -2). which of the following could be its equation?
professor190 [17]

Answer:

B

Since the vertex is (-3,-2) The x value should be +3

7 0
3 years ago
Read 2 more answers
A recipe calls for 1/3 of a cup of milk for 12 cookies. How many cups of milk are needed to make 72 cookies?
uysha [10]
2 cups of milk would be needed to make 72 cookies
7 0
3 years ago
Is the following statement a good definition? Why? An integer is divisible by 100 if and only if its last two digits are zeros.
kifflom [539]
The given statement is:
An integer is divisible by 100 if and only if its last two digits are zeros

The two conditional statements that can be made are:

1) If an integer is divisible by 100 its last two digits are zeros.

This is a true statement. If a number is divisible by 100, it means 100 must be a factor of that number. When 100 will be multiplied by the remaining factors, the number will have last two digits zeros. 

2) If the last two digits of an integer are zeros, it is divisible by 100.

This is also true. If last two digits are zeros, this means 100 is a factor of the integer. So the number will be divisible by 100.

Therefore, the two conditional statements that are formed are both true.

So, the option A is the correct answer.
Yes, it is. When the definition is separated into two conditional statements, both of the statements are true
6 0
3 years ago
Researchers are studying the distribution of subscribers to a certain streaming service in different populations. From a random
Katen [24]

Answer:

CI = (0.17 - 0.27)\± 1.65\sqrt{\frac{(0.17)*(0.83) + (0.27)*(0.73)}{200}}

Step-by-step explanation:

Given

n = 200

x_1 = 34 -- City C

x_2 = 54 --- City K

Required

Determine the 90% confidence interval

This is calculated using:

CI = \bar x \± z\frac{\sigma}{\sqrt n}

Calculating \bar x

\bar x = \bar x_1 - \bar x_2

\bar x = \frac{x_1}{n} - \frac{x_2}{n}

\bar x = \frac{34}{200} - \frac{54}{200}

\bar x = 0.17 - 0.27

For a 90% confidence level, the ​z-score is 1.65.  So:

z = 1.65

Calculating the standard deviation \sigma

\sigma = \sqrt{(\bar x_1)*(1 - \bar x_1) + (\bar x_2)*(1 - \bar x_2) }

So:

\sigma = \sqrt{(0.17)*(1 - 0.17) + (0.27)*(1 - 0.27) }

\sigma = \sqrt{(0.17)*(0.83) + (0.27)*(0.73)}

So:

CI = (0.17 - 0.27)\± 1.65\frac{\sqrt{(0.17)*(0.83) + (0.27)*(0.73)}}{\sqrt {200}}

CI = (0.17 - 0.27)\± 1.65\sqrt{\frac{(0.17)*(0.83) + (0.27)*(0.73)}{200}}

7 0
2 years ago
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