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2 years ago

15 a2 − 1 = 5 2a − 2 Which equation results from cross-multiplying?

2 answers:

7 0

Given the expression:
15/(a²-1)=5/(2a-2)
cross-multiplying the above we get:
15×(2a-2)=5×(a²-1)
this will give us:
15(2a-2)=5(a²-1)

Answer: b]<span>15(2a – 2) = 5(a2 – 1)</span>

vaieri [72.5K]2 years ago

4 0

Answer:

Option (b) is correct.

${15}(2a-2)={5}(a^2-1)$ equation results from cross-multiplying.

Step-by-step explanation:

Given : expression $\frac{15}{a^2-1}=\frac{5}{2a-2}$

We have to find the results obtained from cross-multiplying the given expression and choose the correct option from given options.

Consider the given expression $\frac{15}{a^2-1}=\frac{5}{2a-2}$

Cross multiply is done by Multiplying the top and bottom of the first fraction by the bottom number of the second fraction.

Thus, for the given expression $\frac{15}{a^2-1}=\frac{5}{2a-2}$

We have,

${15}(2a-2)={5}(a^2-1)$

Thus, option (b) is correct.

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The combined ages of a dog and his owner are 96 years in total. The owner is 3 times older than his dog. How old is the owner?

nikitadnepr [17]

Answer:

72 yrs old.

Step-by-step explanation:

The combined age

D+O=96

The owner is 3 times older than dog

O=3D

D+3D=96

4D = 96

D= 24

Now substitute the value of D in O=3D

O=3.24= 72

The owner is 72 years old.

5 0

2 years ago

The word geometry has eight letters. three letters are chosen at random. what is the probability that two consonants and one vow

olga nikolaevna [1]

Answer:

0.536 is the required probability.

Step-by-step explanation:

We have been given the word the word "GEOMETRY"

we have to find the probability that two consonants and one vowel are chosen:

Number of consonants are: 5

Number of vowels are: 3

Hence, The required probability is: $\frac{^5C_2\cdot ^3C_1}{^8C_3}$

Using: $^nC_r=\frac{n!}{(r!)(n-r)!}$

$\frac{\frac{5!}{3!\cdot 2!}\cdot\frac{3!}{1!\cdot 2!}}{\frac{8!}{3!\cdot 5!}}$

Simplifying the above expression:

$\frac{\frac{5\cdot 4\cdot 3!}{3!\cdot 2}\cdot {\frac{3\cdot 2!}{2!}}}{\frac{8\cdot 7\cdot 6\cdot 5!}{5!\cdot 3\cdot 2}}$

Further simplification after cancelling out the common terms we get:

$\Rightarrow \frac{30}{56}=\frac{15}{28}=0.5357=0.536$

Hence, Option 1 is correct.

4 0

2 years ago

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A remote-controlled plane is flying 16.5 meters above the ground. The plane dives 8 meters

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Answer:

Step-by-step explanation:

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2 years ago

Solve X-9+2wx=y for x

maxonik [38]

X - 9 + 2wx = y Add 9 to both sides x + 2wx = y + 9 Factor out the x x (1 + 2w) = y + 9 Divide both sides by (1 + 2w) x = (y + 9) / (1 + 2w)

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2 years ago

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A factory makes propeller drive shafts for ships. A quality assurance engineer at the factory needs to estimate the true mean le

borishaifa [10]

Answer:

$1000-1.96\frac{2}{\sqrt{4}}=998.04$

$1000+1.96\frac{2}{\sqrt{4}}=1001.96$

Step-by-step explanation:

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".

Solution to the problem

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 0.95 or 95%, the value of $\alpha=0.05$ 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: "=-NORM.INV(0.025,0,1)".And we see that $z_{\alpha/2}=1.96$

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

$1000-1.96\frac{2}{\sqrt{4}}=998.04$

$1000+1.96\frac{2}{\sqrt{4}}=1001.96$

5 0

2 years ago