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Helen [10]
3 years ago
12

Use the distributive property to find the equivalent expression. 7(7 + 6b) =

Mathematics
2 answers:
Ratling [72]3 years ago
7 0

Answer:

49 + 42b

Step-by-step

You are using the distributive property, Take the 7 on the outside, and multiply it by both numbers on the inside.

7 * 7 = 49

7 * 6b = 42b

49 + 42b

otez555 [7]3 years ago
3 0
7x7= 49

7x6b= 42b


49+42b
You might be interested in
Parallelogram JKLM is shown. If KR=X+7, KM = 3x - 5. and JL = 4x - 10.
Lorico [155]

Answer:

Step-by-step explanation:

In a parallelogram, this one in particular:

KR = RM

JR = RL

We are looking in the end for the length of JR, but that means that we need to solve for x somehow to plug in the expression for JL, and then split that in half. Here's how we're going to go about it. I know that

KM = KR + RM, but since KR and RM are the same length, the equation becomes

KM = 2KR. Filling that in with the expressions I'm given for KM and KR:

3x - 5 = 2(x + 7) and

3x - 5 = 2x + 14 and

x = 19. Now I can find the length of JL:

JL = 4x - 10 so

JL = 4(19) - 10 and

JL = 66

Knowing that JR = RL and JL is 66 units long, JR = RL = 33 units each.

3 0
3 years ago
Suppose the method of tree ring dating gave the following dates A.D. for an archaeological excavation site. Please show your wor
natita [175]

Answer:

a) \bar X=\frac{1245+1245+1321+1191+1295+1330+1239+1250+1228}{9}= 1260.444

b) s =\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}

And if we replace we got:

s = 45.580

c) For this case since the sampel size is n=9 <30 we can use the t distribution in order to find the confidence interval.

d) 1260.444-2.306 \frac{45.580}{\sqrt{9}}= 1225.408

1260.444+2.306 \frac{45.580}{\sqrt{9}}= 1295.480

Step-by-step explanation:

For this case we ave the following data:

1245 1245 1321 1191 1295 1330 1239 1250 1228

Part a

We can calculate the sample mean with the following formula:

\bar X = \frac{\sum_{i=1}^n X_i}{n}

And if we replace we got:

\bar X= \frac{1245+1245+1321+1191+1295+1330+1239+1250+1228}{9}= 1260.444

Part b

For this case we can use the following formula in order to find the sample standard deviation:

s =\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}

And if we replace we got:

s = 45.580

Part c

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".

For this case since the sampel size is n=9 <30 we can use the t distribution in order to find the confidence interval.

Part d

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 given by:

df = n-1 = 9-1=8

Since the Confidence is 0.95 or 95%, the value of \alpha=1-0.95=0.05 and \alpha/2 =0.025, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,8)".And we see that t_{\alpha/2}=2.306

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

1260.444-2.306 \frac{45.580}{\sqrt{9}}= 1225.408

1260.444+2.306 \frac{45.580}{\sqrt{9}}= 1295.480

   

   

8 0
4 years ago
Please help me with this math question
Alja [10]

Answer:

5.50 years

Step-by-step explanation:

A = P(1 + \frac{r}{n})^{nt}

A = final amount

P = initial principal balance

r = interest rate

n = number of times interest applied per time period

t = number of time periods elapsed

3178 = 2000(1+.086/2)^2t

t = 5.499904413

7 0
3 years ago
Rhett is solving the quadratic equation 0= x2 – 2x – 3 using the quadratic formula. Which shows the correct substitution of the
posledela
Formulas, answers and solutions are in the file. 

x= (2 +- 4)/2

x1= 3; x2= -1

Download docx
6 0
3 years ago
Question 132 .. .. .. .. ..
Eddi Din [679]

Answer:

∠LOM is 48°

Step-by-step explanation:

∠MOL+∠MON=180°

6x°+12°+7x°-92°=180°

13x°-80°=180°

<em>Add 80° to both sides</em>

13x°=260°

<em>Divide both sides by 13</em>

x°=20°

Plugging x° into the equation for ∠LOM, we get:

7×20°-92°=

140°-92°=

48°

∠LOM is 48°

4 0
3 years ago
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