What are the roots of the equation 5x^2=-9x-6n simplest a+bi form?

The price of a notebook was $3.70 yesterday. Today, the price fell to $3.20. Find the percent decrease

jeyben [28]

Answer:

86% Decrease

Step-by-step explanation:

3.70 times x= 3.20 3.20 divided by 3.70= 0.86

6 0

3 years ago

Adrian took out a simple interest loan for $2000. The rate on this loan is 7% and he will pay it back in 5 years. How much money

laila [671]

Answer:

i think its 700

Step-by-step explanation:

7%of 2000 is 140 and 140 x 5 is 700

8 0

3 years ago

Read 2 more answers

A chemist examines 12 sedimentary samples for bromide concentraction. The mean bromide concentration for the sample date is 0.43

Umnica [9.8K]

Answer:

a) $z = 1.645$

b) Lower endpoint: 0.422cc/m³

Upper endpoint: 0.452 cc/m³

Step-by-step explanation:

Population is approximately normal, so we can find the normal confidence interval.

We have that to find our $\alpha$ level, that is the subtraction of 1 by the confidence interval divided by 2. So:

$\alpha = \frac{1-0.9}{2} = 0.05$

Now, we have to find z in the Ztable as such z has a pvalue of $1-\alpha$ .

So it is z with a pvalue of $1-0.05 = 0.95$ , so $z = 1.645$ . This is the critical value, the answer for a).

Now, find M as such

$M = z*\frac{\sigma}{\sqrt{n}}$

In which $\sigma$ is the standard deviation of the population and n is the size of the sample.

$M = 1.645*\frac{0.0325}{\sqrt{12}} = 0.015$

The lower end of the interval is the sample mean subtracted by M. So it is 0.437 - 0.015 = 0.422cc/m³.

The upper end of the interval is the sample mean added to M. So it is 0.437 + 0.015 = 0.452 cc/m³.

b)

Lower endpoint: 0.422cc/m³

Upper endpoint: 0.452 cc/m³

4 0

3 years ago

I need help with #8. I need to use the quadratic formula. I have a calculator that is programmed for the quadratic formula so al

GuDViN [60]

Answer:

x = 14

Step-by-step explanation:

Extend line AB so that it intersects ray CE at point G. Then angles BGC and BAD are "alternate interior angles", hence congruent.

The angle at B is exterior to triangle BCG, and is equal to the sum of the interior angles at C and G:

138 = (376 -23x) +(x^2 -8x)

Subtracting 138 and collecting terms we have ...

x^2 -31x +238 = 0

For your calculator, a=1, b=-31, c=238.

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<em>Additional comment</em>

You will find that the solutions to this are x = {14, 17}. You will also find that angle BCE will have corresponding values of 54° and -15°. That is, the solution x=17 is "extraneous." It is a solution to the equation, but not to the problem.

For x=14, the marked angles are A = 84°, C = 54°.

8 0

3 years ago

Y=<br> Pls help solve for

miss Akunina [59]

Answer:

$y=39\degree$

Step-by-step explanation:

The given triangle is a right angle triangle .

The known sides of the triangle that is opposite to angle y is 8 units while the side adjacent is 10 units.

The value of y can be calculated using the tangent ratio.

$\tan(y)=\frac{8}{10}$

We solve for y to get,

$y=arctan(\frac{4}{5})$

We evaluate to obtain,

$y=38.66$

$y=39\degree$ to the nearest degree

8 0

3 years ago