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3 years ago

Solve for b. ab+c=d B=a+c/d B=a/(c-d) B=(d-c)/a

Mathematics

1 answer:

vekshin13 years ago

3 0

Answer:

b = (d-c)/a

Step-by-step explanation:

ab+c=d

Subtract c from each side

ab+c-c=d-c

ab = d-c

Divide by a

ab/a = (d-c)/a

b = (d-c)/a

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Can someone explain to me the letter or sign or variable after "Y"

sattari [20]

Answer:

It is a symbol used to denote an angle (or something else)

Step-by-step explanation:

Alpha(α) is a greek letter, it's one of the letters used to denote angles. Other such letters you'll often see in math are Beta (β), Gamma (γ), Delta (δ), these are used to denote angles. Also, pi (π), which is a mathematical constant. The letters phi (φ) and theta (θ) are also used for angles very often, especially in formulas. You'll see some of these in physics too.

It can be used as variable too, not necessarily for angles, but it's mostly used for them.

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3 years ago

Help i know it but my brain isnt working because of anxiety

Flauer [41]

Answer:

It's angles 2 and 5

Step-by-step explanation:

Supplementary angles or angles that are obtuse or over 90°

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3 years ago

Read 2 more answers

Can someone solve for x please

aleksandrvk [35]

Answer:

x=-4

Step-by-step explanation:

The two lines are parallel, so the two angles, 45 and x+49 are equal too

Lets make the equation

x+49 = 45

x = 45-49

x = -4

If my answer is incorrect, pls correct me!

If you like my answer and explanation, mark me as brainliest!

-Chetan K

8 0

3 years ago

<img src="https://tex.z-dn.net/?f=%24a%2Ba%20r%2Ba%20r%5E%7B2%7D%2B%5Cldots%20%5Cinfty%3D15%24%24a%5E%7B2%7D%2B%28a%20r%29%5E%7B

riadik2000 [5.3K]

Let

$S_n = \displaystyle \sum_{k=0}^n r^k = 1 + r + r^2 + \cdots + r^n$

where we assume |r| < 1. Multiplying on both sides by r gives

$r S_n = \displaystyle \sum_{k=0}^n r^{k+1} = r + r^2 + r^3 + \cdots + r^{n+1}$

and subtracting this from $S_n$ gives

$(1 - r) S_n = 1 - r^{n+1} \implies S_n = \dfrac{1 - r^{n+1}}{1 - r}$

As n → ∞, the exponential term will converge to 0, and the partial sums $S_n$ will converge to

$\displaystyle \lim_{n\to\infty} S_n = \dfrac1{1-r}$

Now, we're given

$a + ar + ar^2 + \cdots = 15 \implies 1 + r + r^2 + \cdots = \dfrac{15}a$

$a^2 + a^2r^2 + a^2r^4 + \cdots = 150 \implies 1 + r^2 + r^4 + \cdots = \dfrac{150}{a^2}$

We must have |r| < 1 since both sums converge, so

$\dfrac{15}a = \dfrac1{1-r}$

$\dfrac{150}{a^2} = \dfrac1{1-r^2}$

Solving for r by substitution, we have

$\dfrac{15}a = \dfrac1{1-r} \implies a = 15(1-r)$

$\dfrac{150}{225(1-r)^2} = \dfrac1{1-r^2}$

Recalling the difference of squares identity, we have

$\dfrac2{3(1-r)^2} = \dfrac1{(1-r)(1+r)}$

We've already confirmed r ≠ 1, so we can simplify this to

$\dfrac2{3(1-r)} = \dfrac1{1+r} \implies \dfrac{1-r}{1+r} = \dfrac23 \implies r = \dfrac15$

It follows that

$\dfrac a{1-r} = \dfrac a{1-\frac15} = 15 \implies a = 12$

and so the sum we want is

$ar^3 + ar^4 + ar^6 + \cdots = 15 - a - ar - ar^2 = \boxed{\dfrac3{25}}$

which doesn't appear to be either of the given answer choices. Are you sure there isn't a typo somewhere?

7 0

2 years ago

the speed of a stream is 4mph. If a boat travels 92 miles downstream in the same time that it takes to travel 46 miles upstream,

Elanso [62]

Answer:

12 miles per hour

Step-by-step explanation:

Let speed of boat in still water be "x"

and speed of current be "c"

So, downstream rate would be "x + c"

And, upstream rate would be "x - c"

Now, given c = 4

We can use the distance formula, D = RT, where

D is distance, R is rate, and T is time

to solve this.

Downstream:

D = RT

92 = (x+4)(t)

Upstream:

D = RT

46 = (x-4)(t)

Both the times are same, we can equate both the times. Lets simplify first:

t = 92/(x+4)

and

t = 46/(x-4)

Equate:

$\frac{92}{x+4}=\frac{46}{x-4}$

Now, cross multiply and solve for x to get our answer:

$\frac{92}{x+4}=\frac{46}{x-4}\\92(x-4)=46(x+4)\\92x-368=46x+184\\46x=552\\x=12$

Speed of Boat (in still water) = 12 mph

6 0

3 years ago