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3 years ago

Factor x2 -12x + 36

Mathematics

1 answer:

zhannawk [14.2K]3 years ago

4 0

Answer:

(x -6)²

Step-by-step explanation:

It is worth remembering the form of the square of a binomial:

(a +b)² = a² +2ab +b²

Note that if "a" and "b" have different signs, the middle term will be negative.

In your case, the square root of the constant is half the magnitude of the x-coefficient, so the trinomial you have is a perfect square. Since you just found √36 = 6, and the sign of 12 tells you the terms have different signs, you know the answer is ...

x² -12x +36 = (x -6)²

_____

Of course, you recognize (x +6)(x -6) as the factoring of the difference of squares ...

x² -6² = x² -36

which is not what you have.

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M is the midpoint of QR M = (-2,6) Q= (8,-10) R = ????

Zolol [24]

Answer:

R = (-12, 22)

Step-by-step explanation:

Unfortunately it's not a straight line, so gonna need to put in some extra work. Basically think of it like breaking it into it's horizontal and vertical components then doubling them.

From Q to M you move 10 spaces to the left, so to go from M to R you will go another 10 to the left. Similarly, you start at -10 for the y value and go up 16 to 6, and you will need to go up another 16 to get to R.

So for x, 8 -10 = -2 then -2 - 10 = -12, so R's x value is -12

y we do the same thing. Gonna do it in one step though. -10 + 16 + 16 = 22

So R is (-12, 22)

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3 years ago

a dining room table and chairs are priced at $869. Mrs. Brown has a coupon for $75 off the original price. If the tax on the sal

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869 * .08 = 69.52
69.52 + 869 = 938.52
938.52- 75 = 863.52

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3 years ago

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The price of a laptop is $420. The price of a phone is 35% of the price of this laptop. What is the price of the phone? A $12 B

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The correct answer would be B. $420x0.35=$147.00

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ASAP PLSSS help me with this math question

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Step-by-step explanation:

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3 years ago

A quality control expert at LIFE batteries wants to test their new batteries. The design engineer claims they have a variance of

iris [78.8K]

Answer:

The probability that the mean battery life would be greater than 533.2 minutes (in a sample of 75 batteries) is $\\ P(z>0.48) = P(x>533.2) = 0.3156$

Step-by-step explanation:

The main thing we have to take into account in this question is that we are about to find the probability of a sample mean. The distribution for sample means follows a normal distribution with mean $\\ \mu$ and standard deviation $\\ \frac{\sigma}{\sqrt{n}}$ . Mathematically

$\\ \overline{x} \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

For values of the sample $\\ n \ge 30$ , no matter the distribution the data come from.

And the variable z follows a standard normal distribution, and, as we can remember, this distribution has a mean = 0 and a standard deviation = 1. Mathematically

$\\ z = \frac{\overline{x} - \mu}{\frac{\sigma}{\sqrt{n}}}$ [1]

That is

$\\ z \sim N(0, 1)$

We have a variance of 3364. That is, a standard deviation of

$\\ \sigma^2 = 3364; \sigma = \sqrt{3364} = 58$

The population mean is

$\\ \mu = 530$

The sample size is $\\ n = 75$

The sample mean is $\\ \overline{x} = 533.2$

With all this information, we can solve the question

The probability that the mean battery life would be greater than 533.2 minutes

Using equation [1]

$\\ z = \frac{\overline{x} - \mu}{\frac{\sigma}{\sqrt{n}}}$

$\\ z = \frac{533.2 - 530}{\frac{58}{\sqrt{75}}}$

$\\ z = \frac{3.2}{\frac{58}{8.66025}}$

$\\ z = \frac{3.2}{6.69726}$

$\\ z = 0.47780$

With this value of z we can consult a cumulative standard normal table (or use some statistic program) to find the cumulative probability for z (and remember that this variable follows a standard normal distribution).

Most standard normal tables have values for z for only two decimals, so we can round the previous value for z as z = 0.48.

Then

$\\ P(z$

However, in the question we are asked for $\\ P(z>0.48) = P(x>533.2)$ . As well as all normal distributions, the standard normal distribution is symmetrical around the mean, and we have

$\\ P(z>0.48) = 1 - P(z$

Thus

$\\ P(z>0.48) = 1 - 0.68439$

$\\ P(z>0.48) = 0.31561$

Rounding to four decimal places, we have

$\\ P(z>0.48) = 0.3156$

So, the probability that the mean battery life would be greater than 533.2 minutes is (in a sample of 75 batteries) $\\ P(z>0.48) = P(x>533.2) = 0.3156$ .

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