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tia_tia [17]
2 years ago
15

Explain answer ! Will give brainlst

Mathematics
1 answer:
Marrrta [24]2 years ago
7 0

To solve a multi-variable problem, you need to isolate single variables. To do this, there are two ways to do it. One way you eliminate one of the variables and the other you substitute.

In this example, you are being asked to eliminate one of the variables. To do this, you multiply 2x+2y= 12 by 2 and get 4x+4y = 24.

See how now both equations contain a 4y?

Using this you can subtract one equation from the other.

5x+4y=28

- 4x+4y=24

And then you get x=4

To get the other variable, you substitute 4 in for x (in one of the equations) and then solve for y.

2(4) + 2y =12

8+2y= 12

2y=4

y=2

Therefore, x = 4 and y = 2

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Answer:

1.) A, B, and E

2.) (0, 0)

3.) -2

4.) f(x) ≥ 3

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Step-by-step explanation:

4 0
2 years ago
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The amount of time devoted to studying statistics each week by students who achieve a grade of A in the course is a normally dis
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Answer:

a) 11.7% of students study for more than 10 hours per week.    

b) 35.6% of student spends between 7 and 9 hours studying.

c) 1.6% of  students spend fewer than 3 hours studying.

d) 5% of all A students spend studying 4.0455 or less hours during a week.

Step-by-step explanation:

We are given the following information in the question:

Mean, μ = 7.5 hours

Standard Deviation, σ = 2.1 hours

We are given that the distribution of amount of time is a bell shaped distribution that is a normal distribution.

Formula:

z_{score} = \displaystyle\frac{x-\mu}{\sigma}

a) P(students study for more than 10 hours per week)

P(x > 10)

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b) P(student spends between 7 and 9 hours studying.)

P(7 \leq x \leq 9) = P(\displaystyle\frac{7 - 7.5}{2.1} \leq z \leq \displaystyle\frac{9-7.5}{2.1}) = P(-0.2380 \leq z \leq 0.7142)\\\\= P(z \leq 0.7142) - P(z < -0.2380)\\= 0.762 - 0.406 = 0.356 = 35.6\%

P(7 \leq x \leq 9) = 35.6\%

c)  P(students spend fewer than 3 hours studying)

P(x < 3) = P(z < \displaystyle\frac{3-7.5}{2.1}) = P(z < -2.1428)

Calculating the value from the standard normal table we have,

P( x < 3) =0.016 = 1.6\%

d)  P(X < x) = 0.05

We have to find the value of x such that the probability is 0.035

P( X < x) = P( z < \displaystyle\frac{x - 7.5}{2.1})=0.05  

Calculation the value from standard normal z table, we have,  

\displaystyle\frac{x - 7.5}{2.1} = -1.645\\x = 4.0455  

5% of all A students spend studying 4.0455 or less hours during a week.

5 0
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How many solutions can be found for the equation 4z + 2(z - 4) = 3z + 11
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