Evaluate -x for x = -3.

If we are given x such that 25^x-9^y=18 and 5^x-3^y=3, compute 5^x+3^y.

leonid [27]

25 = 5*5 and 9 = 3*3, which we can exploit to write

$25^x-9^y=(5^2)^x-(3^2)^y=5^{2x}-3^{2y}=(5^x)^2-(3^y)^2$

so that this expression is actually a difference of squares. We can factorize this to get

$(5^x-3^y)(5^x+3^y)=18$

and given that $5^x-3^y=3$ , we divide both sides by this to get

$5^x+3^y=\dfrac{18}3=\boxed{6}$

7 0

3 years ago

PLEASE HELP FAST!!! Estimate the line of best fit using two points on the line.

FrozenT [24]

Answer:

D) y= -1/2x+9

Step-by-step explanation:

if u substitute y with 8 u will get 2

if u substitute y with 5 u will get 8

3 0

2 years ago

Read 2 more answers

According to the text, the specific things that people want in life are called

Oksi-84 [34.3K]

Answer:

your going to have to be a little more specific than that please ;-; but if you want i can answer it this way

Reach a fabled level of success that makes you untouchable.

Create a positive work/life balance.

Feel as capable as others think you are.

Be more productive with each minute of the day.

Be recognized as talented or even brilliant.

4 0

3 years ago

Suppose <img src="https://tex.z-dn.net/?f=m" id="TexFormula1" title="m" alt="m" align="absmiddle" class="latex-formula"> men and

ollegr [7]

Firstly, we'll fix the postions where the $n$ women will be. We have $n!$ forms to do that. So, we'll obtain a row like:

$\underbrace{\underline{~~~}}_{x_2}W_2 \underbrace{\underline{~~~}}_{x_3}W_3 \underbrace{\underline{~~~}}_{x_4}... \underbrace{\underline{~~~}}_{x_n}W_n \underbrace{\underline{~~~}}_{x_{n+1}}$

The n+1 spaces represented by the underline positions will receive the men of the row. Then,

$x_1+x_2+x_3+...+x_{n-1}+x_n+x_{n+1}=m~~~(i)$

Since there is no women sitting together, we must write that $x_2,x_3,...,x_{n-1},x_n\ge1$ . It guarantees that there is at least one man between two consecutive women. We'll do some substitutions:

$\begin{cases}x_2=x_2'+1\\x_3=x_3'+1\\...\\x_{n-1}=x_{n-1}'+1\\x_n=x_n'+1\end{cases}$

The equation (i) can be rewritten as:

$x_1+x_2+x_3+...+x_{n-1}+x_n+x_{n+1}=m\\\\
x_1+(x_2'+1)+(x_3'+1)+...+(x_{n-1}'+1)+x_n+x_{n+1}=m\\\\
x_1+x_2'+x_3'+...+x_{n-1}'+x_n+x_{n+1}=m-(n-1)\\\\
x_1+x_2'+x_3'+...+x_{n-1}'+x_n+x_{n+1}=m-n+1~~~(ii)$

We obtained a linear problem of non-negative integer solutions in (ii). The number of solutions to this type of problem are known: $\dfrac{[(n)+(m-n+1)]!}{(n)!(m-n+1)!}=\dfrac{(m+1)!}{n!(m-n+1)!}$

[I can write the proof if you want]

Now, we just have to calculate the number of forms to permute the men that are dispposed in the row: $m!$

Multiplying all results:

$n!\times\dfrac{(m+1)!}{n!(m-n+1)!}\times m!\\\\
\boxed{\boxed{\dfrac{m!(m+1)!}{(m-n+1)!}}}$

4 0

3 years ago

If you want to buy an item in a store that cost $43 and is on sale for 40% off, then how much would the item actually cost you a

expeople1 [14]

Answer:

$25.80

Step-by-step explanation:

40% = 40/ 100 = 4/10 = 0,4

There is a 40% discount, which means that the amount multiplied by more then 1 (for example 1,4) would increase the amount... That isn't right because it is a discount!

So you need to subtract the 40%, so (1 - 0.4 =) 0.6

The amount multiplied by 0.6 will be the correct amount, being $43 * 0.6 = $25.80 (rounded to the nearest cent).

The amount the item actually cost after the discount is $25.80

4 0

3 years ago