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3 years ago

I need help with percent and tax

Mathematics

1 answer:

sasho [114]3 years ago

6 0

Hello there

56•25/100=

1400÷100=

14$

56-14=42$

He will pay 42$

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I need answers to this

ololo11 [35]

Answer:

x = -5, and y = -6

Step-by-step explanation:

Suppose that we have two equations:

A = B

and

C = D

combining the equations means that we will do:

First we multiply both whole equations by constants:

k*(A = B) ---> k*A = k*B

j*(C = D) ----> j*C = j*D

And then we "add" them:

k*A + j*C = k*B + j*D

Now we have the equations:

-x - y = 11

4*x - 5*y = 10

We want to add them in a given form that one of the variables cancels, so we can solve it for the other variable.

Then we can take the first equation:

-x - y = 11

and multiply both sides by 4.

4*(-x - y = 11)

Then we get:

4*(-x - y) = 4*11

-4*x - 4*y = 44

Now we have the two equations:

-4*x - 4*y = 44

4*x - 5*y = 10

(here we can think that we multiplied the second equation by 1, then we have k = 4, and j = 1)

If we add them, we get:

(-4*x - 4*y) + (4*x - 5*y) = 10 + 44

-4*x - 4*y + 4*x - 5*y = 54

-9*y = 54

So we combined the equations and now ended with an equation that is really easy to solve for y.

y = 54/-9 = -6

Now that we know the value of y, we can simply replace it in one of the two equations to get the value of x.

-x - y = 11

-x - (-6) = 11

-x + 6 = 11

-x = 11 -6 = 5

-x = 5

x = -5

Then:

x = -5, and y = -6

5 0

3 years ago

The volume

Sedaia [141]

$\bf \begin{array}{cccccclllll}
\textit{something}&&\textit{varies directly to}&&\textit{something else}\\ \quad \\
\textit{something}&=&{{ \textit{some value}}}&\cdot &\textit{something else}\\ \quad \\
y&=&{{ k}}&\cdot&x
&& y={{ k }}x
\end{array}\\ \quad \\
$

and also

$\bf \begin{array}{llllll}
\textit{something}&&\textit{varies inversely to}&\textit{something else}\\ \quad \\
\textit{something}&=&\cfrac{{{\textit{some value}}}}{}&\cfrac{}{\textit{something else}}\\ \quad \\
y&=&\cfrac{{{\textit{k}}}}{}&\cfrac{}{x}
&&y=\cfrac{{{ k}}}{x}
\end{array}
$

now, we know that V varies directly to T and inversely to P simultaneously
thus $\bf V=T\cdot \cfrac{k}{P}$

so $\bf V=T\cdot \cfrac{k}{P}\qquad 
\begin{cases}
V=42\\
T=84\\
P=8
\end{cases}\implies 42=\cfrac{84k}{8}\implies 4=k
\\\\\\
V=\cfrac{4T}{P}\qquad now\quad 
\begin{cases}
V=74\\
P=10
\end{cases}\implies 74=\cfrac{4T}{10}\implies 185=T$