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2 years ago

What is the value of the variable? 3(x- 2)=15

Mathematics

1 answer:

STatiana [176]2 years ago

4 0

Answer:

x=7

Step-by-step explanation:

To solve for x, you have to multiply the terms in parenthesis by 3. Then you add 6 to each side of the equal sign. Then you divide each side of the equal sign by 3 to get x=7

$3x-6=15\\3x=15+6\\3x=21\\x=21/3\\x=7$

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katrin2010 [14]

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Step-by-step explanation:

8 0

3 years ago

The amount of money spent on textbooks per year for students is approximately normal.

Ostrovityanka [42]

Answer:a

$336.04 < \mu < 443.96$

The margin of error will increase

The margin of error will decreases

The 99% confidence interval is $0.4107 < p < 0.4293$

Step-by-step explanation:

From the question we are told that

The sample size $n = 19$

The sample mean is $\= x = \$\ 390$

The standard deviation is $\sigma = \$ \ 120$

Given that the confidence level is 95% then the level of significance is mathematically represented as

$\alpha = 100 - 95$

$\alpha = 5 \%$

$\alpha = 0.05$

Next we obtain the critical value of $\frac{\alpha }{2}$ from the normal distribution table

$Z_{\frac{\alpha }{2} } = 1.96$

The margin of error is mathematically represented as

$E = Z_{\frac{\alpha }{2} } * \frac{\sigma}{\sqrt{n} }$

=> $E = 1.96 * \frac{120}{\sqrt{19} }$

=> $E = 53.96$

The 95% confidence interval is

$\= x - E < \mu < \= x + E$

=> $390 - 53.96 < \mu < 390 - 53.96$

=> $336.04 < \mu < 443.96$

When the confidence level increases the $Z_{\frac{\alpha }{2} }$ also increases which increases the margin of error hence the confidence level becomes wider

Generally the sample size mathematically varies with margin of error as follows

$n \ \ \alpha \ \ \frac{1}{E^2 }$

So if the sample size increases the margin of error decrease

The sample proportion is mathematically represented as

$\r p = \frac{210}{500}$

$\r p = 0.42$

Given that the confidence level is 0.99 the level of significance is $\alpha = 0.01$

The critical value of $\frac{\alpha }{2}$ from the normal distribution table is

$Z_{\frac{\alpha }{2} } = 2.58$

Generally the margin of error is mathematically represented as

$E = Z_{\frac{\alpha }{2} }* \sqrt{ \frac{\r p (1- \r p )}{n} }$

=> $E = 0.42 * \sqrt{ \frac{0.42 (1- 0.42 )}{ 500} }$

=> $E = 0.0093$

The 99% confidence interval is

$\r p - E < p < \r p + E$

$0.42 - 0.0093 < p < 0.42 + 0.0093$

$0.4107 < p < 0.4293$

4 0

3 years ago

Please help me with this!!!

Dafna1 [17]

Answer:

option C is correct answer ..

Step-by-step explanation:

angle A + angle B + angle C = 180° ( by angle sum property of triangle )

3x + 4x-19+ 3x -1 = 180

10x + -20 = 180

10x = 180 +20 = 200

x = 200/10 = 20 °

angle A = 3× 20 = 60 °

angle B = 4× 20 - 1 9 = 61 °

angle C = 3× 20 -1 = 59 °

angle B is greatest so side opposite to it will be greatest in length ....so length of AC is greatest ....

so option C is the correct answer of this question ...

plz mark my answer as brainlist plzzzz vote me also as I have done this question by taking a lot of time Hope it will be helpful for you ....

5 0

2 years ago

¿Cuántas esferas hay en la figura 20?

scoundrel [369]

Answer:

418

Step-by-step explanation:

fig 2 = fig 1 + 5

fig 3 = fig 2 + 7 or fig 1 +5+7 16

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

4+5+7+9+11+13+15+17+18+19+21+23+25+27+29+31+33+35+37+39

8 0

3 years ago

Which expression is equivalent to 27 + 45? 8(3 + 6) 8(19 + 37) 9(3 + 5) 9(18 + 36)

Sladkaya [172]

9(3+5) is equivalent because factoring a 9 out of both 27 and 45 leaves us with 9(3+5).

4 0

3 years ago

Read 2 more answers