16x 2 + 8x - 15 Mathematics?

1 answer:

5 0

If you're factoring, your answer is

(4x - 3)(4x + 5)

You'll work it out this way:

16x^2 + 8x - 15

Since there's no GCF here, you multiply the first and third terms, giving you -240. Your next step is to find two numbers that have a sum of 8 and a product of -240. These numbers are 20 and -12. Plug those in and you've got:

16x^2 + 20x - 12x - 15

From here you divide it into two binomials. These are (16x^2 + 20x) and (-12x - 15).
When you take out the greatest common factors (4x and -3), they become:

4x(4x + 5) - 3(4x + 5)

Then you group what's outside of the parentheses together (4x - 3)
And bring what's inside of the parentheses down (4x + 5).
This brings your answer to

(4x - 3)(4x + 5)

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Alexander deposited money into his retirement account that is compounded annually at an interest rate of 7%.

anzhelika [568]

Tow rates are equivalent if tow initial investments over a the same time, produce the same final value using different interest rates.

For the annually rate we have that:
$V_{0} =(1+ i_{a} ) ^{1}$
Where
$V_{0}$ = initial investment.
$i_{a}$ = annually interest rate in decimal form.
And the exponent (1) represents the full year.

For the quarterly interest rate we have that:
$V_{0} =(1+ i_{q} ) ^{4}$
Where
$V_{0}$ = initial investment.
$i_{q}$ = quarterly interest rate in decimal form.
And the exponent (4) the 4 quarters in the full year.

Since the rates are equivalent if tow initial investments over a the same time, produce the same final value, then
$(1+ i_{a} )=(1+ i_{q} ) ^{4}$
Notice that we are not using the initial investment $V_{0}$ since they are the same.

The first thin we are going to to calculate the equivalent quarterly rate of the 7% annually rate is converting 7% to decimal form
7%/100 = 0.07
Now, we can replace the value in our equation to get:
$(1+0.07)=(1+ i_{q} ) ^{4}$
$1.07=(1+ i_{q} ) ^{4}$
$\sqrt[4]{1.07} =1+ i_{q}$
$i_{q} = \sqrt[4]{1.07} -1$
$i_{q} =0.017$
Finally, we multiply the quarterly interest rate in decimal form by 100% to get:
(0.017)(100%) = 1.7%
We can conclude that Alexander is wrong, the equivalent quarterly rate of an annually rate of 7% is 1.7% and not 2%.

6 0

3 years ago

12. If a manufacturer conducted a survey among randomly selected target market households and wanted to be 95% confident that th

atroni [7]

Answer:

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

And rounded up we have that n=1068

Step-by-step explanation:

We have the following info given:

$Confidence= 0.95$ the confidence level desired

$ME =0.03$ represent the margin of error desired

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)

The confidence level is 95% or 0.95, the significance is $\alpha=0.05$ and the critical value for this case using the normal standard distribution would be $z_{\alpha/2}=1.96$