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3 years ago

What is the answer for -5x^2=-500 by factoring the quadratic equation?

Mathematics

1 answer:

evablogger [386]3 years ago

5 0

Answer:

x=10

Step-by-step explanation:

I think..i tired

Divide both sides by 55.

{x}^{2}=-\frac{500}{5}x2=−5500

Simplify \frac{500}{5}5500 to 100100.

{x}^{2}=-100x2=−100

Take the square root of both sides.

x=\pm \sqrt{-100}x=±√−100

Simplify \sqrt{-100}√−100 to \sqrt{100}\imath√100ı.

x=\pm \sqrt{100}\imathx=±√100ı

Since 10\times 10=10010×10=100, the square root of 100100 is 1010.

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6÷2(1+2) = x

Korolek [52]

Answer:

X =9

Step-by-step explanation:

$6 \div 2(1 + 2) = x \\ 6 \div 2(3) = x \\ x = \frac{6}{2} \times 3 \\ x = 3 \times 3 \\ x = 9$

4 0

3 years ago

Victoria rides her bike at a constant rate of 1 3/8 miles every 1/4 hour. What is her speed in miles per hour?

NISA [10]

Answer:

5 1/2 miles per 1 hr

Step-by-step explanation:

biked 1 3/8 miles in 1/ of an hour

1 3/8 miles = 11/8 miles in 1/4 of hour

11/8 miles divided by 1/4 hr

11/8 ÷ 1/4

11/8 * 4/1 =44/8 = 5 4/8 miles in 1 hr or 5 1/2 miles per 1 hr

6 0

3 years ago

Please help with steps as well!

AnnZ [28]

Answer:

y = 72.5 cm

Step-by-step explanation:

We know that tan theta = opposite/ adjacent

tan 30 = x/y

tan 30 =36.25/y

Multiply each side by y

y tan 30 = 36.25y/y

y tan 30 = 26.25

Divide each side by tan 30

y tan 30 / tan 30 = 36.25/tan 30

y = 36.25/ tan 30

y =72.5

6 0

4 years ago

Of 1000 randomly selected cases of lung cancer, 823 resulted in death within 10 years.

Arada [10]

Answer:

a) $0.823 - 1.96\sqrt{\frac{0.823(1-0.823)}{1000}}=0.799$

$0.823 + 1.96\sqrt{\frac{0.823(1-0.823)}{1000}}=0.847$

The 95% confidence interval would be given by (0.799;0.847)

b) $n=\frac{0.823(1-0.823)}{(\frac{0.03}{1.96})^2}=621.79$

And rounded up we have that n=622

c) $n=\frac{0.5(1-0.5)}{(\frac{0.03}{1.96})^2}=1067.11$

And rounded up we have that n=1068

Step-by-step explanation:

Part a

$\hat p=\frac{823}{1000}=0.823$

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 95% of confidence, our significance level would be given by $\alpha=1-0.95=0.05$ and $\alpha/2 =0.025$ . And the critical value would be given by:

$z_{\alpha/2}=-1.96, z_{1-\alpha/2}=1.96$

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

$\hat p \pm z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$

If we replace the values obtained we got:

$0.823 - 1.96\sqrt{\frac{0.823(1-0.823)}{1000}}=0.799$

$0.823 + 1.96\sqrt{\frac{0.823(1-0.823)}{1000}}=0.847$

The 95% confidence interval would be given by (0.799;0.847)

Part b

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.03$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

And replacing into equation (b) the values from part a we got:

$n=\frac{0.823(1-0.823)}{(\frac{0.03}{1.96})^2}=621.79$

And rounded up we have that n=622

Part c

$n=\frac{0.5(1-0.5)}{(\frac{0.03}{1.96})^2}=1067.11$

And rounded up we have that n=1068

5 0

3 years ago

There are 4 aces and 4 kings in a standard deck of 52 cards. You pick onecard at random. What is the probability of selecting an

Anna007 [38]

The odds of picking a single card out of 52 is:
1/52

The odds of picking an Ace is:

4/52 (since there are 4 aces in a single deck)

The odds of picking an ace or a king is:

8/52 (since there are 4 aces and 4 kings in a single deck, 4+4=8_

8/52 can be simplified to 2/13

Answer=2/13

6 0

4 years ago