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3 years ago

Solve for x: 3(x-4)=12

Mathematics

2 answers:

levacccp [35]3 years ago

7 0

The answer would be x=8

zaharov [31]3 years ago

3 0

First, do distributive property. 3 • x and 3 • -4. Now you get 3x-12=12. Now add 12 to both sides. Now you have 3x=24. Now divide by 3 to get your x alone and you answer which is 8!

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<img src="https://tex.z-dn.net/?f=%28-1%7B2%7D%7B3%7D%20%29x%5E%7B3%7D" id="TexFormula1" title="(-1{2}{3} )x^{3}" alt="(-1{2}{3}

Alex_Xolod [135]

After talking with you here are two different options I think you are trying to ask:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you are talking about: $(\frac{-12}{3}) ^{3}$

Answer: -62

Explanation:

PEMDAS tells us we need to do the exponent first:

-12³ = (-12)³ = -1728

<em>The parentheses are important so you cube the negative sign as well!</em>

3³ = 27

-1728 / 27 = -62

$(\frac{-12}{3}) ^{3}$ simplified is -62

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If you are talking about (-1 $\frac{2}{3}$ )³

Answer: - $\frac{125}{27}$

Explanation:

First, let us turn -1 and two thirds into a mixed number:

Ignoring the negative for now, we can 1 times 3 is 3. 3 plus 2 is 5. 5/3 is 5/3. Adding in the negative we get $-\frac{5}{3}$

To cube it we must do:

( $-\frac{5}{3}$ )( $-\frac{5}{3}$ )( $-\frac{5}{3}$ )

3 times 3 (9) times 3 is 27

5 times 5 (25) times 5 is 125

So we have 125/27

For the negative, we have three - - -

Two cancel each other out, and we are left with one (-) so our answer is negative

(-1 $\frac{2}{3}$ )³ simplifed is - $\frac{125}{27}$

7 0

3 years ago

Which vector best describes the translation below?

Nimfa-mama [501]

<h3>Answer: Choice A) <9,0></h3>

Explanation:

Focus on one of the points in the figure on the left. Let's say we go for the upper left corner point (-7, 4)

Notice it moves to the corresponding image point (2,4). It has shifted 9 units to the right to follow the translation rule $(x,y) \to (x+9, y)$ . We've added 9 to the x coordinate, and the y coordinate stays the same.

This notation can be shortened to <9, 0>

In general, the notation $(x,y) \to (x+a, y+b)$ is shortened to the translation vector notation $< a, b >$ . In this case, a = 9 and b = 0.

8 0

2 years ago

A random sample of 10 parking meters in a beach community showed the following incomes for a day. Assume the incomes are normall

Vlad1618 [11]

Answer: (2.54,6.86)

Step-by-step explanation:

Given : A random sample of 10 parking meters in a beach community showed the following incomes for a day.

We assume the incomes are normally distributed.

Mean income : $\mu=\dfrac{\sum^{10}_{i=1}x_i}{n}=\dfrac{47}{10}=4.7$

Standard deviation : $\sigma=\sqrt{\dfrac{\sum^{10}_{i=1}{(x_i-\mu)^2}}{n}}$

$=\sqrt{\dfrac{(1.1)^2+(0.2)^2+(1.9)^2+(1.6)^2+(2.1)^2+(0.5)^2+(2.05)^2+(0.45)^2+(3.3)^2+(1.7)^2}{10}}$

$=\dfrac{30.265}{10}=3.0265$

The confidence interval for the population mean (for sample size <30) is given by :-

$\mu\ \pm t_{n-1, \alpha/2}\times\dfrac{\sigma}{\sqrt{n}}$

Given significance level : $\alpha=1-0.95=0.05$

Critical value : $t_{n-1,\alpha/2}=t_{9,0.025}=2.262$

We assume that the population is normally distributed.

Now, the 95% confidence interval for the true mean will be :-

$4.7\ \pm\ 2.262\times\dfrac{3.0265}{\sqrt{10}} \\\\\approx4.7\pm2.16=(4.7-2.16\ ,\ 4.7+2.16)=(2.54,\ 6.86)$

Hence, 95% confidence interval for the true mean= (2.54,6.86)

7 0

4 years ago

For the function y=400-22x, what is the rate of change

dolphi86 [110]

Answer:

-22

Step-by-step explanation:

The function y=400-22x is a linear equation in the form y=mx + b. Although they put "mx" after "b" so the equation doesn't start with a negative.

"m" is rate of change, or the slope if graphed.

The negative means "y" decreases as "x" increases. On a graph, it decreases left to right.

8 0

3 years ago

Rationalise the denominator of:<br>1/(√3 + √5 - √2)

Paul [167]

Step-by-step explanation:

$\large\underline{\sf{Solution-}}$

Given expression is

$\rm :\longmapsto\:\dfrac{1}{ \sqrt{3} + \sqrt{5} - \sqrt{2} }$

can be re-arranged as

$\rm :\longmapsto\:\dfrac{1}{ \sqrt{3} - \sqrt{2} + \sqrt{5} }$

$\rm \: = \: \dfrac{1}{( \sqrt{3} - \sqrt{2} ) + \sqrt{5} }$

On rationalizing the denominator, we get

$\rm \: = \: \dfrac{1}{( \sqrt{3} - \sqrt{2} ) + \sqrt{5} } \times \dfrac{( \sqrt{3} - \sqrt{2} ) - \sqrt{5} }{( \sqrt{3} - \sqrt{2} ) - \sqrt{5} }$

We know,

$\rm :\longmapsto\:\boxed{\tt{ (x + y)(x - y) = {x}^{2} - {y}^{2} \: }}$

So, using this, we get

$\rm \: = \: \dfrac{ \sqrt{3} - \sqrt{2} - \sqrt{5} }{ {( \sqrt{3} - \sqrt{2} )}^{2} - {( \sqrt{5}) }^{2} }$

$\rm \: = \: \dfrac{ \sqrt{3} - \sqrt{2} - \sqrt{5} }{3 + 2 - 2 \sqrt{6} - 5}$

$\rm \: = \: \dfrac{ \sqrt{3} - \sqrt{2} - \sqrt{5} }{5 - 2 \sqrt{6} - 5}$

$\rm \: = \: \dfrac{ \sqrt{3} - \sqrt{2} - \sqrt{5} }{ - 2 \sqrt{6}}$

$\rm \: = \: \dfrac{ - ( - \sqrt{3} + \sqrt{2} + \sqrt{5}) }{ - 2 \sqrt{6}}$

$\rm \: = \: \dfrac{- \sqrt{3} + \sqrt{2} + \sqrt{5}}{2 \sqrt{6}}$

On rationalizing the denominator, we get

$\rm \: = \: \dfrac{- \sqrt{3} + \sqrt{2} + \sqrt{5}}{2 \sqrt{6}} \times \dfrac{ \sqrt{6} }{ \sqrt{6} }$

$\rm \: = \: \dfrac{- \sqrt{18} + \sqrt{12} + \sqrt{30}}{2 \times 6}$

$\rm \: = \: \dfrac{- \sqrt{3 \times 3 \times 2} + \sqrt{2 \times 2 \times 3} + \sqrt{30}}{12}$

$\rm \: = \: \dfrac{- 3\sqrt{2} + 2 \sqrt{3} + \sqrt{30}}{12}$

Hence,

$\boxed{\tt{ \rm \dfrac{1}{ \sqrt{3} + \sqrt{5} - \sqrt{2} } =\dfrac{- \sqrt{3 \times 3 \times 2} + \sqrt{2 \times 2 \times 3} + \sqrt{30}}{12}}}$

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<h3><u>More Identities to </u><u>know:</u></h3>

$\purple{\boxed{\tt{ {(x - y)}^{2} = {x}^{2} - 2xy + {y}^{2}}}}$

$\purple{\boxed{\tt{ {(x + y)}^{2} = {x}^{2} + 2xy + {y}^{2}}}}$

$\purple{\boxed{\tt{ {(x + y)}^{3} = {x}^{3} + 3xy(x + y) + {y}^{3}}}}$

$\purple{\boxed{\tt{ {(x - y)}^{3} = {x}^{3} - 3xy(x - y) - {y}^{3}}}}$

$\pink{\boxed{\tt{ {(x + y)}^{2} + {(x - y)}^{2} = 2( {x}^{2} + {y}^{2})}}}$

$\pink{\boxed{\tt{ {(x + y)}^{2} - {(x - y)}^{2} = 4xy}}}$

6 0

3 years ago