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2 years ago

A student solved a system of equations by elimination. Describe and correct the error made in the part of the solution shown.

Mathematics

1 answer:

ivanzaharov [21]2 years ago

7 0

Answer:

x = -2; y = 3

Step-by-step explanation:

5x + 4y = 2 (1)

3x + 3y = 3 (2)

Multiply (1) by 3 and (2) by 4

15x + 12y = 6 (3)

12x + 12y = 12 (4)

Subtract (4) from (3)

15x - 12x = 6 - 12

3x = -6

x = -6/3

x = -2

Substitute x = -2 into (1)

5x + 4y = 2

5(-2) + 4y = 2

-10 + 4y = 2

4y = 2 +10

4y = 12

y = 12/4

y = 3

The first error is when he multiplied equation (2) by 4

He didn't multiply the right hand side of the equation by 4

3x + 3y = 3 ×4

12x + 12y = 12

But he wrote

12x + 12y = 3

The the next error is subtracting the left hand side of the equation and adding the right hand side

15x + 12y = 6

12x + 12y = 3

He wrote

3x = 9

Instead of 3x = 3

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Answer:

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Step-by-step explanation:

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3 years ago

Solve: 2x2-x = 21 {-7/2,3} {-3, 7/2}

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Answer:

The answer is (-3,7/2)

Step-by-step explanation:

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2 years ago

12x+7=3x-1 slove for x

alexdok [17]

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3 years ago

The television show CSI: Shoboygan has been successful for many years. That show recently had a share of 18, meaning that among

jeyben [28]

Answer:

(a) The value of P (None) is 0.062.

(b) The value of P(at least one) is 0.938.

(d) The event is not unusual.

Step-by-step explanation:

Let X = number of households watching the show.

The probability of the random variable x is, P (X) = p = 0.18.

The sample selected for the survey is of size, n = 14

The random variable X follows a Binomial distribution with parameter n = 14 and p = 0.18.

The probability of a Binomial distribution is computed using the formula:

$P(X=x)={n\choose x}p^{x}(1-p)^{n-x};\ x=0,1,2,...$

(a)

Compute the probability that none of the households are tuned to CSI: Shoboygan as follows:

$P(X=0)={14\choose 0}(0.18)^{0}(1-0.18)^{14-0}=1\times1\times0.06214=0.062$

Thus, the value of P (None) is 0.062.

(b)

Compute the probability that at least one household is tuned to CSI: Shoboygan as follows:

P (X ≥ 1) = 1 - P (X < 1)

= 1 - P (X = 0)

$=1-0.062\\=0.938$

Thus, the value of P(at least one) is 0.938.

(c)

Compute the probability that at most one household is tuned to CSI: Shoboygan as follows:

P (X ≤ 1) = P (X = 0) + P (X = 1)

$={14\choose 0}(0.18)^{0}(1-0.18)^{14-0}+{14\choose 1}(0.18)^{1}(1-0.18)^{14-1}\\=0.062+0.191\\=0.253$

Thus, the value of P(at most one) is 0.253.

(d)

An event that has a very low probability of occurrence is known as an unusual event.

The probability of the event "at most one household is tuned to CSI: Shoboygan" is 0.253.

This probability value is not low.

Hence, the event is not unusual.

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3 years ago