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Aliun [14]
3 years ago
13

Solve each system by elimination -3x-6y=-3 5x+5y=0

Mathematics
1 answer:
serious [3.7K]3 years ago
8 0

Answer:

x=1 and y=−1

Step-by-step explanation:

Multiply the first equation by 5,and multiply the second equation by 6.

5(−3x−6y=3)

6(5x+5y=0)

Becomes:

−15x−30y=15

30x+30y=0

Add these equations to eliminate y:

15x=15

Then solve15x=15for x:

15x=15

15x

15

=

15

15

(Divide both sides by 15)

x=1

Now that we've found x let's plug it back in to solve for y.

Write down an original equation:

−3x−6y=3

Substitute1forxin−3x−6y=3:

(−3)(1)−6y=3

−6y−3=3(Simplify both sides of the equation)

−6y−3+3=3+3(Add 3 to both sides)

−6y=6

−6y

−6

=

6

−6

(Divide both sides by -6)

y=−1

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insens350 [35]

Answer: 3+3=9

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Step-by-step explanation: three fingers to start add three fingers total of nine

4 0
2 years ago
Does anyone know how to do this? And can you also help me with this problem, thank you :)
GenaCL600 [577]
<span>Multiply equation(2) with 4 so that coefficient of become same in both the equations(You can make coefficient of y same and can follow the following procedure.) 
</span><span>* Subtract (3) from (1) 
* </span>Divide both sides by -19
*Subtract 21 from both sides.
*Divide both sides by 4
so the solution is     x= 3 and  y= -7
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6 0
3 years ago
Evelyn wants to estimate the percentage of people who own a tablet computer she surveys 150 indvidals and finds that 120 own a t
igomit [66]

Answer:

The 99% confidence interval for the percentage of people who own a tablet computer is between 71.59% and 88.41%

Step-by-step explanation:

Confidence interval for the proportion of people who own a tablet:

In a sample with a number n of people surveyed with a probability of a success of \pi, and a confidence level of 1-\alpha, we have the following confidence interval of proportions.

\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}

In which

z is the zscore that has a pvalue of 1 - \frac{\alpha}{2}.

For this problem, we have that:

n = 150, \pi = \frac{120}{150} = 0.8

99% confidence level

So \alpha = 0.01, z is the value of Z that has a pvalue of 1 - \frac{0.01}{2} = 0.995, so Z = 2.576.

The lower limit of this interval is:

\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.8 - 2.575\sqrt{\frac{0.8*0.2}{150}} = 0.7159

The upper limit of this interval is:

\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.8 + 2.575\sqrt{\frac{0.8*0.2}{150}} = 0.8841

Percentage:

Multiply the proportion by 100.

0.7159*100 = 71.59%

0.8841*100 = 88.41%

The 99% confidence interval for the percentage of people who own a tablet computer is between 71.59% and 88.41%

8 0
3 years ago
Which of the following correctly factors the expression −20x+4y−2?
Wewaii [24]

9514 1404 393

Answer:

  B  2(−10x+2y−1)

Step-by-step explanation:

The greatest common factor is 2. Factoring that out gives the factorization shown in choice B.

  2(-10x +2y -1)

__

You could factor out -2. Doing that would give ...

  -2(10x -2y +1) . . . . . . . doesn't match choice C

8 0
3 years ago
kalia spent a quarter of her weekly allowance on a movie. the movie was $4.25. WHat is her weekly allowance
Montano1993 [528]

Answer:

$17

Step-by-step explanation:

Think about it like this.

$4.25 is equal to 0.25 * x value, where x is the weekly allowance

$4.25=0.25x

$17=x

7 0
3 years ago
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