Can someone help me with section b please and thank you

Solve the system of linear equations by substitution. y = 2x + 8 y = -2x

posledela

Answer:

(- 2, 4 )

Step-by-step explanation:

y = 2x + 8 → (1)

y = - 2x → (2)

substitute y = 2x + 8 into (2)

2x + 8 = - 2x ( add 2x to both sides )

4x + 8 = 0 ( subtract 8 from both sides )

4x = - 8 ( divide both sides by 4 )

x = - 2

substitute x = - 2 into (2)

y = - 2(- 2) = 4

solution is (- 2, 4 )

6 0

2 years ago

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Customers arrive at a movie theater at the advertised movie time only to find that they have to sit through several previews and

balu736 [363]

Answer:

(a) The sample size required is 43.

(b) The sample size required is 62.

Step-by-step explanation:

The (1 - α) % confidence interval for population mean is:

$CI=\bar x\pm z_{\alpha/2}\ \frac{\sigma}{\sqrt{n}}$

The margin of error for this interval is:

$MOE=z_{\alpha/2}\ \frac{\sigma}{\sqrt{n}}$

(a)

The information provided is:

σ = 4 minutes

MOE = 72 seconds = 1.2 minutes

Confidence level = 95%

α = 5%

Compute the critical value of z for α = 5% as follows:

$z_{\alpha/2}=z_{0.05/2}=z_{0.025}=1.96$

*Use a z-table.

Compute the sample size required as follows:

$MOE=z_{\alpha/2}\ \frac{\sigma}{\sqrt{n}}$

$n=[\frac{z_{\alpha/2}\times \sigma}{MOE} ]^{2}$

$=[\frac{1.96\times 4}{1.2}]^{2}\\\\=42.684\\\\\approx 43$

Thus, the sample size required is 43.

(b)

The information provided is:

σ = 4 minutes

MOE = 1 minute

Confidence level = 95%

α = 5%

Compute the critical value of z for α = 5% as follows:

$z_{\alpha/2}=z_{0.05/2}=z_{0.025}=1.96$

*Use a z-table.

Compute the sample size required as follows:

$MOE=z_{\alpha/2}\ \frac{\sigma}{\sqrt{n}}$

$n=[\frac{z_{\alpha/2}\times \sigma}{MOE} ]^{2}$

$=[\frac{1.96\times 4}{1}]^{2}\\\\=61.4656\\\\\approx 62$

Thus, the sample size required is 62.

3 0

2 years ago

Find exact value for cos(pi/16)

stellarik [79]

The exact value for cos(pi/16) would be :

cos (pi/16) = +/- √1+cosa/2

cos (pi/4) = sqrt2/2

Hope this helps

6 0

3 years ago

V-16=-32 I need help with the math worksheet how to solve the question

sergeinik [125]

You solve an equation like this by adding the opposite of the constant to both sides of the equation.

... V -16 +16 = -32 +16 . . . . . addition property of equality: if a=c, then a+b = c+b

... V + 0 = -16 . . . . . . . . . . . . additive inverse property of integers: -16+16 = 0

... V = -16 . . . . . . . . . . . . . . . identity element of addition: V+0 = V

_____

You can always do the same thing to both sides of an equation. Here, it is useful to add the opposite of -16 to both sides. That way the constant on the left becomes zero, so you only have the variable by itself—which is what you want.

8 0

3 years ago

The total rainfall in Forks, Washington, this October was 8 3/8 in. In September, 60% less rain fell than in October.

lakkis [162]

Given:
October: 8 3/8 inches
September : 60% less rain fell than in October.

This means that only 40% rain fell in September based on the amount of rain that fell in October.

8 3/8 ⇒ (8*8)+3/8 = 67/8
40% is 4/10

67/8 * 4/10 = 268/80 = 3 28/80 or 3 7/20 or 3.35

28 ÷ 2 = 14
80 ÷ 2 = 40
14 ÷ 2 = 7
40 ÷ 2 = 20

In September 3 7/20 inches or 3.35 inches of rain fell.

7 0

3 years ago

Read 2 more answers

Can someone help me with section b please and thank you ​

Can someone help me with section b please and thank you