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3 years ago

Doing some more so please help

Mathematics

2 answers:

RSB [31]3 years ago

7 0

Multiply 9*5*4*7.

hen square that.

ohaa [14]3 years ago

6 0

The second one just had this yesterday

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A circle has the order pairs (-1, 2) (0, 1) (-2, -1) what is the equation . Show your work.

olga55 [171]

We know that:

$(x-a)^2+(y-b)^2=r^2$

is an equation of a circle.

When we substitute x and y (from the pairs we have), we'll get a system of equations:

$\begin{cases}(-1-a)^2+(2-b)^2=r^2\\(0-a)^2+(1-b)^2=r^2\\(-2-a)^2+(-1-b)^2=r^2\end{cases}$

and all we have to do is solve it for a, b and r.

There will be:

$\begin{cases}(-1-a)^2+(2-b)^2=r^2\\(0-a)^2+(1-b)^2=r^2\\(-2-a)^2+(-1-b)^2=r^2\end{cases}\\\\\\
\begin{cases}1+2a+a^2+4-4b+b^2=r^2\\a^2+1-2b+b^2=r^2\\4+4a+a^2+1+2b+b^2=r^2\end{cases}\\\\\\
\begin{cases}a^2+b^2+2a-4b+5=r^2\\a^2+b^2-2b+1=r^2\\a^2+b^2+4a+2b+5=r^2\end{cases}\\\\\\
$

From equations (II) and (III) we have:

$\begin{cases}a^2+b^2-2b+1=r^2\\a^2+b^2+4a+2b+5=r^2\end{cases}\\--------------(-)\\\\a^2+b^2-2b+1-a^2-b^2-4a-2b-5=r^2-r^2\\\\-4a-4b-4=0\qquad|:(-4)\\\\\boxed{-a-b-1=0}$

and from (I) and (II):

$\begin{cases}a^2+b^2+2a-4b+5=r^2\\a^2+b^2-2b+1=r^2\end{cases}\\--------------(-)\\\\a^2+b^2+2a-4b+5-a^2-b^2+2b-1=r^2-r^2\\\\2a-2b+4=0\qquad|:2\\\\\boxed{a-b+2=0}$

Now we can easly calculate a and b:

$\begin{cases}-a-b-1=0\\a-b+2=0\end{cases}\\--------(+)\\\\-a-b-1+a-b+2=0+0\\\\-2b+1=0\\\\-2b=-1\qquad|:(-2)\\\\\boxed{b=\frac{1}{2}}\\\\\\\\a-b+2=0\\\\\\a-\dfrac{1}{2}+2=0\\\\\\a+\dfrac{3}{2}=0\\\\\\\boxed{a=-\frac{3}{2}}$

Finally we calculate $r^2$ :

$a^2+b^2-2b+1=r^2\\\\\\\left(-\dfrac{3}{2}\right)^2+\left(\dfrac{1}{2}\right)^2-2\cdot\dfrac{1}{2}+1=r^2\\\\\\\dfrac{9}{4}+\dfrac{1}{4}-1+1=r^2\\\\\\\dfrac{10}{4}=r^2\\\\\\\boxed{r^2=\frac{5}{2}}$

And the equation of the circle is:

$(x-a)^2+(y-b)^2=r^2\\\\\\\left(x-\left(-\dfrac{3}{2}\right)\right)^2+\left(y-\dfrac{1}{2}\right)^2=\dfrac{5}{2}\\\\\\\boxed{\left(x+\dfrac{3}{2}\right)^2+\left(y-\dfrac{1}{2}\right)^2=\dfrac{5}{2}}$

7 0

3 years ago

Need help with this please

OLga [1]

Answer:

k= -2

Step-by-step explanation:

you are dividing the x by -2 each time

3 0

3 years ago

Number 7 using algorithm

aniked [119]

Sorry it says plus but its times

6 0

4 years ago

An assembly line has two inspectors. The probability that the first inspector will miss a defective item is 0.06. If the defecti

Novay_Z [31]

Answer:

probability that both passes a defective item is 0.8742‬

<h3>Step-by-step explanation:</h3>

probability that the first inspector misses is Pr( 1st misses)= 0.06

therefore the probability he does not miss is

Pr(1st passes)= 1 - Pr( 1st misses) = 1 - 0.06 = 0.94

probability that the second misses is Pr( 2nd misses) = 0.07

therefore probability that 2nd does not miss is

Pr( 2nd passes) = 1- Pr( 2nd misses) = 0.93

probability that both passes a defective item is Pr(1st passes)*Pr( 2nd passes)

= 0.93*0.94 = 0.8742‬

7 0

3 years ago

How much more interest is earned on an investment of $12,585 at 3.5% interest over 5 years if the interest is compounded annuall

Nina [5.8K]

Answer:

It is B.$159.65

Step-by-step explanation:

I got it the test

7 0

3 years ago

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