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3 years ago

If x2 – 49 = (x+a) (x – a), what is the value of a?

Mathematics

2 answers:

Ivenika [448]3 years ago

7 0

Answer:

a = 7 & a = −7

Explanation:

Rewrite the equation as

(x+a)(x−a)=x^2−49

Simplify (x+a)(x−a)

x^2−a^2=x^2−49

Move all terms not containing a to the right side of the equation.

−a^2=−49

Multiply each term in −a^2=−49 by −1

a^2=49

Take the square root of both sides of the equation to eliminate the exponent on the left side.

a=±√49

The complete solution is the result of both the positive and negative portions of the solution.

a=7,−7

vaieri [72.5K]3 years ago

5 0

Answer:

a is 7

Step-by-step explanation:

x²-49

so you are finding the difference of squares

and if you look closely, you can see that the equation has squares.

49 has the square root of 7, but the rules on squares state that the squared number comes in both positive and negative numbers.

so a is equal to both -7 and +7

PS i hope this helps

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Can anyone help me with this? giving brainliest to correct answer!

Mekhanik [1.2K]

Answer:

-24

Step-by-step explanation:

P=26/27

Q=-2/3

10q-18p

10(-2/3)-18(26/27)=-24

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3 years ago

Two random samples are taken, with each group asked if they support a particular candidate. A summary of the sample sizes and pr

Minchanka [31]

Answer:

And we got $\alpha/2 =0.01$ so then the value for $\alpha=0.02$ and then the confidence level is given by: $Conf=1-0.02=0.98[/tex[ or 98%Step-by-step explanation:A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval". The margin of error is the range of values below and above the sample statistic in a confidence interval. Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean". [tex]p_1$ represent the real population proportion for 1

$\hat p_1 =0.768$ represent the estimated proportion for 1

$n_1=92$ is the sample size required for 1

$p_2$ represent the real population proportion for 2

$\hat p_2 =0.646$ represent the estimated proportion for 2

$n_2=95$ is the sample size required for 2

$z$ represent the critical value for the margin of error

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{p(1-p)}{n}})$

The confidence interval for the difference of two proportions would be given by this formula

$(\hat p_1 -\hat p_2) \pm z_{\alpha/2} \sqrt{\frac{\hat p_1(1-\hat p_1)}{n_1} +\frac{\hat p_2 (1-\hat p_2)}{n_2}}$

For this case we have the confidence interval given by: (-0.0313,0.2753). From this we can find the margin of erro on this way:

$ME= \frac{0.2753-(-0.0313)}{2}=0.1533$

And we know that the margin of erro is given by:

$ME=z_{\alpha/2} \sqrt{\frac{\hat p_1(1-\hat p_1)}{n_1} +\frac{\hat p_2 (1-\hat p_2)}{n_2}}$

We have all the values except the value for $z_{\alpha/2}$

So we can find it like this:

$0.1533=z_{\alpha/2} \sqrt{\frac{0.768(1-0.768)}{92} +\frac{0.646 (1-0.646)}{95}}$

And solving for $z_{\alpha/2}$ we got:

$z_{\alpha/2}=2.326$

And we can find the value for $\alpha/2$ with the following excel code:

"=1-NORM.DIST(2.326,0,1,TRUE)"

And we got $\alpha/2 =0.01$ so then the value for $\alpha=0.02$ and then the confidence level is given by: $Conf=1-0.02=0.98$ or 98%

7 0

3 years ago

There are 12 people in cafe. half of them are drinking coffee. How many people are drinking coffee?

enot [183]

The answer is 6 people.

Half of the 12 people in the cafe would be 6 people. You can find half of a number by dividing it by two, or multiplying it by .5

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3 years ago

Type the correct answer in the box. Use numerals instead of words. If necessary, use / for the fraction bar. One of the x-interc

Marina CMI [18]

3x^2 + 6x - 10 = 0
3(x^2 + 2x) - 10 = 0
3[ (x + 1)^2 - 1 ] - 10 = 0
3(x+1)^2 - 13 = 0

so the vertex is at (-1,-13)
the roots will be same distance from x = -1
that is a distance 1.08 --1 = 2.08

so other root is approximately -1 -2.08 = -3.08

the other intercept is at (-3.08,0)

5 0

3 years ago

Read 2 more answers

Select the two binomials that are factors of this trinomial x2+10x+16

Zigmanuir [339]

So for this trinomial, I will be factoring by grouping. Firstly, what two terms have a product of 16x^2 and a sum of 10x? That would be 8x and 2x. Replace 10x with 2x + 8x:

$x^2+2x+8x+16$

Next, factor x^2 + 2x and 8x + 16 separately. Make sure that they have the same quantity inside the parentheses: $x(x+2)+8(x+2)$

Now you can rewrite this as $(x+8)(x+2)$ , which is your final answer.

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3 years ago