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2 years ago

Solve the following system by elimination 2x-y=9 and 3x+4y=-14

Mathematics

1 answer:

Fofino [41]2 years ago

6 0

2x - y = 9

3x + 4y = -14

To solve this system using elimination, one of the pairs of variable terms must cancel each other out. Their coefficients must be opposites of each other.

Multiply the top equation by 4.

2x - y = 9

4(2x - y = 9)

8x - 4y = 36

Add the equations together.

8x - 4y = 36

3x + 4y = -14

+___________

11x - 0 = 22

11x = 22

x = 2

Substitute 2 for x into either of the original equations to find y.

2x - y = 9

2(2) - y = 9

4 - y = 9

-y = 5

y = -5

Finally, check work by plugging x- and y-values into each original equation.

2(2) - (-5) = 9 --> 4 + 5 = 9 --> 9 = 9 --> True

3(2) + 4(-5) = -14 --> 6 - 20 = -14 --> -14 = -14 --> True

Answer:

x = 2 and y = -5; (2, -5).

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Step-by-step explanation:

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2 years ago

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Answer:

it's 25, just did it

Step-by-step explanation:

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2 years ago

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How to graph y=2x-4 x+3y=9

NikAS [45]

Answer:

Step-by-step explanation:

The point form: (3,2)

You solve for X

You solve for y

On the Y-axis where the 2 is you go 3 to the right and put your point right there above the 3.
There you have your answer on the graph.

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2 years ago

Which statement is true about the value of |-14|

fomenos

Answer:

Step-by-step explanation:

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The absolute value of any quantity, whether it be a + or - quantity, is zero or positive.

Thus, |-14| = the absolute value of -14 = +14

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3 years ago

Assume that a sample is used to estimate a population proportion p. find the margin of error e that corresponds to the given sta

Leno4ka [110]

Let p be the proportion. Let c be the given confidence level , n be the sample size.

Given: p=0.3, n=1180, c=0.99

The formula to find the Margin of error is

ME = $z _{\alpha/2} \sqrt{\frac{p*(1-p)}{n}}$

Where z (α/2) is critical value of z.

P(Z < z) = α/2

where α/2 = (1- 0.99) /2 = 0.005

P(Z < z) = 0.005

So in z score table look for probability exactly or close to 0.005 . There is no exact 0.005 probability value in z score table. However there two close values 0.0051 and 0.0049 . It means our required 0.005 value lies between these two probability values.

The z score corresponding to 0.0051 is -2.57 and 0.0049 is -2.58. So the required z score will be average of -2.57 and -2.58

(-2.57) + (-2.58) = -5.15

-5.15/2 = -2.575

For computing margin of error consider positive z score value which is 2.575

The margin of error will be

ME = $z _{\alpha/2} \sqrt{\frac{p*(1-p)}{n}}$

= $2.575 \sqrt{\frac{0.30*(1-0.3)}{1180}}$

= 2.575 * 0.0133

ME = 0.0342

The margin of error is 0.0342

7 0

2 years ago