All categories

4 years ago

Write a variable expression for the amount of your budget after b books

1 answer:

wel4 years ago

8 0

Because if let's say you have 400$ for the year, and each book cost 10$. So it would be written as 400-10b since the quantity of books must be multiplied times their cost to calculate whether you are within or outside the budget.

You might be interested in

Can somebody explain how these would be done? The selected answer is incorrect, and I was told "Nice try...express the product b

trapecia [35]

Answer:

Solution ( Second Attachment ) : - 2.017 + 0.656i

Solution ( First Attachment ) : 16.140 - 5.244i

Step-by-step explanation:

Second Attachment : The quotient of the two expressions would be the following,

$6\left[\cos \left(\frac{2\pi }{5}\right)+i\sin \left(\frac{2\pi \:}{5}\right)\right]$ ÷ $2\sqrt{2}\left[\cos \left(\frac{-\pi }{2}\right)+i\sin \left(\frac{-\pi \:}{2}\right)\right]$

So if we want to determine this expression in standard complex form, we can first convert it into trigonometric form, then apply trivial identities. Either that, or we can straight away apply the following identities and substitute,

( 1 ) cos(x) = sin(π / 2 - x)

( 2 ) sin(x) = cos(π / 2 - x)

If cos(x) = sin(π / 2 - x), then cos(2π / 5) = sin(π / 2 - 2π / 5) = sin(π / 10). Respectively sin(2π / 5) = cos(π / 2 - 2π / 5) = cos(π / 10). Let's simplify sin(π / 10) and cos(π / 10) with two more identities,

( 1 ) $\cos \left(\frac{x}{2}\right)=\sqrt{\frac{1+\cos \left(x\right)}{2}}$

( 2 ) $\sin \left(\frac{x}{2}\right)=\sqrt{\frac{1-\cos \left(x\right)}{2}}$

These two identities makes sin(π / 10) = $\frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4}$ , and cos(π / 10) = $\frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}$ .

Therefore cos(2π / 5) = $\frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4}$ , and sin(2π / 5) = $\frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}$ . Substitute,

$6\left[ \left\frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4}+i\left\frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}\right]$ ÷ $2\sqrt{2}\left[\cos \left(\frac{-\pi }{2}\right)+i\sin \left(\frac{-\pi \:}{2}\right)\right]$

Remember that cos(- π / 2) = 0, and sin(- π / 2) = - 1. Substituting those values,

$6\left[ \left\frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4}+i\left\frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}\right]$ ÷ $2\sqrt{2}\left[0-i\right]$

And now simplify this expression to receive our answer,

$6\left[ \left\frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4}+i\left\frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}\right]$ ÷ $2\sqrt{2}\left[0-i\right]$ = $-\frac{3\sqrt{5+\sqrt{5}}}{4}+\frac{3\sqrt{3-\sqrt{5}}}{4}i$ ,

$-\frac{3\sqrt{5+\sqrt{5}}}{4}$ = $-2.01749\dots$ and $\:\frac{3\sqrt{3-\sqrt{5}}}{4}$ = $0.65552\dots$

= $-2.01749+0.65552i$

As you can see our solution is option c. - 2.01749 was rounded to - 2.017, and 0.65552 was rounded to 0.656.

________________________________________

First Attachment : We know from the previous problem that cos(2π / 5) = $\frac{\sqrt{2}\sqrt{3-\sqrt{5}}}{4}$ , sin(2π / 5) = $\frac{\sqrt{2}\sqrt{5+\sqrt{5}}}{4}$ , cos(- π / 2) = 0, and sin(- π / 2) = - 1. Substituting we receive a simplified expression,

$6\sqrt{5+\sqrt{5}}-6i\sqrt{3-\sqrt{5}}$

We know that $6\sqrt{5+\sqrt{5}} = 16.13996\dots$ and $-\:6\sqrt{3-\sqrt{5}} = -5.24419\dots$ . Therefore,

Solution : $16.13996 - 5.24419i$

Which rounds to about option b.

7 0

3 years ago

Calculate the annual return percentage

const2013 [10]

The annual returns will be calculated as follows:
a] Here we use the formula:
A=p(1+r/100)^n
A=future amount
p=principle
r=returns
n=time
We are given:
A=500, p=400, t=1
Plugging the values in the formula we obtain:
500=400(1+r)^1
simplifying and solving for r:
1.25=1+r
thus
r=1.25-1
r=0.25~25%

b] Using the formula above:
A=p(1+r/100)^n
A=2500+100=2600, p=2000, n=1 year
plugging the values in the equation we obtain:
2600=2000(1+r)^1
simplifying and solving for r we obtain:
2600/2000=1+r
1.3=1+r
hence
r=1.3-1
r=0.3~30%

7 0

4 years ago

5. Высота ромба равна 12 дм, что составляет 60% основания. Вычи- сли площадь ромба

Alexandra [31]

Answer:

yes

Step-by-step explanation:

8 0

3 years ago

sally has a part time job mowing lawns so she can save money for a new car. she charges $5 per hour define the independent and d

KengaRu [80]

Answer:

Independent: Amount of hours she works

Dependent: Amount of money she makes

Step-by-step explanation:

The independent variable is the part of the equation that changes. In this case the only thing that changes is how long she works, the amount of money she charges and what she is doing does not change.

The dependent variable is what you measure in the equation. In this case, the amount of money she makes depends on the amount of time she works.

8 0

3 years ago

What is the best definition of a triangle?

NISA [10]

Answer:

A figure formed by 3 segments connecting 3 non-colinear points.

3 0

3 years ago

Read 2 more answers