In the image above x=11 cm. Find the surface area of the figure.

Rewrite x2 − 6x + 7 = 0 in the form (x − a)2 = b, where a and b are integers, to determine the a and b values.

Setler79 [48]

Answer:

Therefore values of a and b are

$a=3\ and\ b = 2$

Step-by-step explanation:

Rewrite $x^{2}-6x+7=0$ in the form

$(x-a)^{2}=b$

where a and b are integers,

To Find:

a = ?

b = ?

Solution:

$x^{2}-6x+7=0$ ..............Given

Which can be written as

$x^{2}-6x=-7$

$(\frac{1}{2} coefficient\ of\ x)^{2}=(\frac{1}{2}\times -6)^{2}=9$

Adding half coefficient of X square on both the side we get

$x^{2}-6x+9=-7+9=2$ ...................( 1 )

By identity we have (A - B)² =A² - 2AB + B²

Therefore,

$x^{2}-6x+9=x^{2}-2\times 3\times x+3^{2}=(x-3)^{2}$

Substituting in equation 1 we get

$(x-3)^{2}=2$

Which is in the form of

$(x-a)^{2}=b$

On comparing we get

a = 3 and b = 2

Therefore values of a and b are

$a=3\ and\ b = 2$

4 0

3 years ago

The realtor and her clients do not know the average home sale price for all of Guelph (500 was actually just a guess). However,

strojnjashka [21]

Answer:

a) The 99% confidence interval would be given by (346.708;453.292)

b) The 99% confidence interval would be given by (338.445;461.555)

Step-by-step explanation:

1) Previous concepts

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".

$\bar X=400$ represent the sample mean for the sample

$\mu$ population mean (variable of interest)

$\sigma=80$ represent the population standard deviation

n=15 represent the sample size

2) Part a

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.005,0,1)".And we see that $z_{\alpha/2}=2.58$

Now we have everything in order to replace into formula (1):

$400-2.58\frac{80}{\sqrt{15}}=346.708$

$400+2.58\frac{80}{\sqrt{15}}=453.292$

So on this case the 99% confidence interval would be given by (346.708;453.292)

3) Part b

For this case we don't know the population deviation so we need to use the t distribution instead the normal standard distribution.

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

We need to find the degrees of freedom first df=n-1=15-1=14

Since the Confidence is 0.99 or 99%, the value of $\alpha=0.01$ and $\alpha/2 =0.005$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.005,14)".And we see that $t_{\alpha/2}=2.98$

Now we have everything in order to replace into formula (1):

$400-2.98\frac{80}{\sqrt{15}}=338.445$

$400+2.98\frac{80}{\sqrt{15}}=461.555$

So on this case the 99% confidence interval would be given by (338.445;461.555)

4 0

3 years ago

5. At Euclid Middle School, of the 30 girls who tried out for the lacrosse team, 12 were selected and of the 40 boys who tried o

kondaur [170]

For the girls:

12:30

Simplifying it, we get:

6: 15
2: 5

For the boys:

16:40

Simplifying it, we get:

8:20
4:10
2:5

So yes, the ratios are both the same for boys and girls.

4 0

3 years ago

The left and right page numbers of an open book are two consecutive integers whose sum is 335 find these page numbers.

almond37 [142]

Answer:

167 and 168

you divide 335 by 2, you get 167.5

so it's gonna be either 166 and 167 or 167 and 168

then you add up 166 and 167, you get 333 (so this is not the answer)

it means the answer is 167 and 168 (167+168=335)

hope it helped, sorry for my bad english

if something is not clear, write a comment I'll answer

3 0

3 years ago

Can you help me to solve this problem

storchak [24]

Answer:

I want to show you how to do this as well, the formula you are working with is a^2+b^2=c^2

Step-by-step explanation:

1.) 8^2+b^2=12^2

64+b^2=144

subtract 64 from both sides

b^2=80

take the square root of 80 and you get

b= 8.9

if you need more help on this let me know, I am going to list the other answers now because to do it all and show work on here is a lot of typing, all of which I will do if you do not understand the first example. Also the c value can ONLY BE THE HYPOTENUSE VALUE. The hypotenuse is the longest side of the triangle. For example, 12 would be the C value on number one and in number two it would be 15.

2.) 14.5

3.) 10.3

4.) 18.8

5.) 8

6.) 15

6 0

3 years ago