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3 years ago

Solve the following by elimination method 11x+15y+23=0 and 7x-2y-20=0

1 answer:

7 0

Let 11x + 15y + 23 = 0 be equation (1)
And 7x - 2y - 20 = 0 be equation (2)

Multiply equation (1) by 2:
22x + 30y + 46 = 0

Multiply equation (2) by 15:
105x - 30y - 300 = 0

Add equations (1) and (2):
22x + 105x + 30y - 30y + 46 - 300 = 0
127x - 254 = 0
127x = 254
x = 254/127
[x = 2]

Substitute x = 2 in equation (1) to find y:
11(2) + 15y + 23 = 0
22 + 15y + 23 = 0
15y + 45 = 0
15y = -45
y = -45/15
y = -3

Therefore, x = 2 and y = -3.

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The town of Hayward (CA) has about 50,000 registered voters. A political research firm takes a simple random sample of 500 of th

timama [110]

Answer: (0.076, 0.140)

Step-by-step explanation:

Confidence interval for population proportion (p) is given by :-

$\hat{p}\pm z_{\alpha/2}\sqrt{\dfrac{\hat{p}(1-\hat{p})}{n}}$

, where $\hat{p}$ = sample proportion.

n= sample size.

$\alpha$ = significance level .

$z_{\alpha/2}$ = critical z-value (Two tailed)

As per given , we have

sample size : n= 500

The number of Independents.: x= 54

Sample proportion of Independents $\hat{p}=\dfrac{x}{n}=\dfrac{54}{500}=0.108$

Significance level 98% confidence level : $\alpha=1-0.98=0.02$

By using z-table , Critical value : $z_{\alpha/2}=z_{0.01}=2.33$

The 98% confidence interval for the true percentage of Independents among Haywards 50,000 registered voters will be :-

$0.108\pm (2.33)\sqrt{\dfrac{0.108(1-0.108)}{500}}\\\\=0.108\pm2.33\times0.013880634\\\\=0.108\pm0.03234187722\\\\\approx0.108\pm0.032=(0.108-0.032,\ 0.108+0.032)=(0.076,\ 0.140)$

Hence, the 98% confidence interval for the true percentage of Independents among Haywards 50,000 registered voters.= (0.076, 0.140)

8 0

3 years ago

Percent proportion definition

sdas [7]

The Percent Proportion is defined by. amount. ... The base, denoted by the letter b, is the entire quantity or total involved. Note: The number that is the base usually appears after the word of. The amount, denoted by the letter a, is the part being compared to the whole or total.

7 0

2 years ago

Read 2 more answers

Find the distance between 2 and -2 A. -6 B -4 C. 0 D. 4

tangare [24]

Answer:

b) -4

Step-by-step explanation:

Well your at 2 and going to -2 so on a number line you be going back or left.

Going two left gets you to zero and going two more get you -2. So in total you went back four and that be represented as -4.

5 0

2 years ago

Jeffrey is scuba diving. His elevation changes by -5.5 inches every second. Jeffrey Dives for 30 seconds. What is the total chan

elena-s [515]

-165...you take -5.5 times 30 and you get -165

8 0

2 years ago

What is the lcm of 2x²and3y

zloy xaker [14]

Answer:

LCM(2x² , 3y) = 6x²y

Step-by-step explanation:

these two expressions 2x²and 3y have no common factor

Then

LCM(2x² , 3y) = 2x² × 3y

= (2×3)x²y

= 6x²y

5 0

1 year ago