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2 years ago

What two numbers multiply to 16 and add to 4?

2 answers:

7 0

You said that (xy) = 16, and (x+y) = 4 .

From the second equation you can get [ x = 4 - y ],
then substitude that for 'x' in the first equation, and
finally, rearrange the first equation to read
 x² - 4x + 16 = 0

Don't even try to factor that quadratic equation. Go straight
to the quadratic formula, and the two solutions you find are ...

 x = 2 + i 2√3
and
 x = 2 - i 2√3 .

Those are the two number that do what you want.

There are no real numbers that can do it.

Brilliant_brown [7]2 years ago

6 0

Xy=16
x + y = 4
-----------------

Solve those two equations for x and y.

The two numbers are: 2 - 2i sqr(3) and 2 + 2i sqr(3)

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I have a whole packet :(

Maslowich

12 A . my guess would be to divide 2175 by 18 which would give you 120.83

7 0

2 years ago

<img src="https://tex.z-dn.net/?f=10-%5Cfrac%7B3y-1%7D%7B2%7D%20%3D%5Cfrac%7B6y%2B3%7D%7B11%7D" id="TexFormula1" title="10-\frac

Ghella [55]

$10-\frac{3x-1}{2} =\frac{6x+3}{11}$

$10 = \frac{6x+3}{11} + \frac{3x-1}{2}$

$10 = (\frac{6x+3}{11} \times \frac{2}{2} ) + (\frac{3x-1}{2} \times \frac{11}{11} )$

$10 = ( \frac{2(6x + 3)}{22} ) + ( \frac{11(3x - 1)}{22} )$

$10 = \frac{12x + 6}{22} + \frac{33x - 11}{22}$

$10 = \frac{12x + 6 + 33x - 11}{22}$

$10 = \frac{(12 x + 33x) + (6 - 11)}{22}$

$10 = \frac{45x - 5}{22}$

$10 \times 22 = 45x - 5$

$220 = 45x - 5$

$220 + 5 = 45x$

$225 = 45x$

$\frac{225}{45} = x$

$\frac{45}{9} = x$

$5 = x$

7 0

1 year ago

A Rasmussen Reports survey of 1,000 US adults found that 42% believe raising the minimum wage will help the economy. Construct a

vitfil [10]

Answer:

(0.3798, 0.4602)

Step-by-step explanation:

Let p be the true proportion of US adults who believe raising the minimum wage will help the economy. A point estimate for p is $\hat{p}=0.42$ and a good aproximation (because we have a large sample) for the standard deviation of $\hat{p}$ is $\sqrt{\hat{p}(1-\hat{p})/n}=\sqrt{0.42(0.58)/1000}=0.0156$ . Therefore, a 99% confidence interval for p is given by $\hat{p}\pm z_{\alpha/2}\sqrt{\frac{\hat{p}(1-\hat{p})}{n}}$ where $\alpha=0.01$ and $z_{\alpha/2}$ is the $\alpha/2$ th quantile of the standard normal distribution, so we have, $0.42\pm z_{0.005}0.0156$ , i.e., $0.42\pm(-2.5758)(0.0156)$ or equivalently (0.3798, 0.4602).

6 0

2 years ago

Which expressions are equivalent??

Brilliant_brown [7]

Given:

The given expression is $2\left(\frac{3}{4} x+7\right)-3\left(\frac{1}{2} x-5\right)$

We need to determine the equivalent expression.

Option A: -1

Solving the expression, we get;

$\frac{3}{2} x+14-\frac{3}{2} x+15$

Simplifying, we get;

$14+15=29$

Thus, the expression $2\left(\frac{3}{4} x+7\right)-3\left(\frac{1}{2} x-5\right)$ is not equivalent to -1.

Hence, Option A is not the correct answer.

Option B: 29

Solving the expression, we get;

$\frac{3}{2} x+14-\frac{3}{2} x+15$

Simplifying, we get;

$14+15=29$

Thus, the expression $2\left(\frac{3}{4} x+7\right)-3\left(\frac{1}{2} x-5\right)$ is equivalent to 29.

Hence, Option B is the correct answer.

Option C: $2\left(\frac{3}{4} x+7\right)+(-3)\left[\frac{1}{2} x+(-5)\right]$

Let us rewrite the given expression.

$2\left(\frac{3}{4} x+7\right)+(-3)\left[\frac{1}{2} x+(-5)\right]$

Thus, the expression $2\left(\frac{3}{4} x+7\right)-3\left(\frac{1}{2} x-5\right)$ is equivalent to $2\left(\frac{3}{4} x+7\right)+(-3)\left[\frac{1}{2} x+(-5)\right]$

Thus, Option C is the correct answer.

Option D: $2\left(\frac{3}{4} x\right)+2(7)+3\left(\frac{1}{2} x\right)+3(-5)$

Rewriting the expression, we get;

$2\left(\frac{3}{4} x+7\right)+(-3)\left[\frac{1}{2} x+(-5)\right]$

Hence, the expression $2\left(\frac{3}{4} x+7\right)-3\left(\frac{1}{2} x-5\right)$ is equivalent not to $2\left(\frac{3}{4} x\right)+2(7)+3\left(\frac{1}{2} x\right)+3(-5)$

Thus, Option D is not the correct answer.

Option E: $2\left(\frac{3}{4} x\right)+2(7)+(-3)\left(\frac{1}{2} x\right)+(-3)(-5)$

Multiplying the terms within the bracket, we get;

$2\left(\frac{3}{4} x\right)+2(7)+(-3)\left(\frac{1}{2} x\right)+(-3)(-5)$

Hence, the expression $2\left(\frac{3}{4} x+7\right)-3\left(\frac{1}{2} x-5\right)$ is equivalent to $2\left(\frac{3}{4} x\right)+2(7)+(-3)\left(\frac{1}{2} x\right)+(-3)(-5)$

Thus, Option E is the correct answer.

4 0

2 years ago

The number of salmon swimming upstream to spawn is approximated by the following function:

umka2103 [35]

Answer:

The water temperature that produces the maximum number of salmon swimming upstream is approximately 12.305 degrees Celsius.

Step-by-step explanation:

Let $S(x) = -x^{3}+2\cdot x^{2}+405\cdot x +4965$ , for $6 \leq x \leq 20$ . $x$ represents the temperature of the water, measured in degrees Celsius, and $S$ is the number of salmon swimming upstream to spawn, dimensionless.

We compute the first and second derivatives of the function:

$S'(x) = -3\cdot x^{2}+4\cdot x +405$ (Eq. 1)

$S''(x) = -6\cdot x +4$ (Eq. 2)

Then we equalize (Eq. 1) to zero and solve for $x$ :

$-3\cdot x^{2}+4\cdot x +405 = 0$

And all roots are found by Quadratic Formula:

$x_{1} \approx 12.305\,^{\circ}C$ , $x_{2}\approx -10.971\,^{\circ}C$

Only the first root is inside the given interval of the function. Hence, the correct answer is:

$x \approx 12.305\,^{\circ}C$

Now we evaluate the second derivative at given result. That is:

$S''(12.305) = -6\cdot (12.305)+4$

$S''(12.305) = -69.83$

According to the Second Derivative Test, a negative value means that critical value leads to a maximum. In consequence, the water temperature that produces the maximum number of salmon swimming upstream is approximately 12.305 degrees Celsius.

5 0

2 years ago