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3 years ago

What is the value of 2x+1 is 20 greater than 8x+5?

Mathematics

2 answers:

11111nata11111 [884]3 years ago

7 0

Answer:

x = -4

Step-by-step explanation:

20 greater than (8x+5) is 8x+5+20 = 8x+25. We are told this is the value of 2x+1:

2x+1 = 8x+25

-24 = 6x . . . . . . subtract 2x+25

-4 = x . . . . . . . . divide by 6

The value of x is -4.

Yuliya22 [10]3 years ago

5 0

Answer:

x = -4

I hope this helps!

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is the equation a true statement when x equals -3 in other words is -3 a solution to the equation 6 x + 5 = 5x +8 + 2x explained

serg [7]

Answer: Yes

Step-by-step explanation: bc 6(-3)+5=5(-3)+8+2(-3)

Becomes -18+5=-15+8+-6 which equals -13 on both sides meaning -3 is a solution

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3 years ago

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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:

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

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3 years ago

In ΔRST, s = 7.3 inches, t = 3.1 inches and ∠R=138°. Find the area of ΔRST, to the nearest 10th of a square inch.

Oksana_A [137]

Answer:

5.1 inches

Step-by-step explanation:

Five triangles make up the pentagon.

The area of each is aside

The area of the pentagon is 5

Substitute values and calculate

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2 years ago

Which decimal number is equivalent to 7/10

Musya8 [376]

Answer:

0.7

Step-by-step explanation:

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3 years ago

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A bag of marbles has 5 red, 2 blue, and 3 green marbles. A marble is randomly selected. What is the probability AS A DECIMAL tha

loris [4]

Answer:

0.25 Hope this helps :)

Step-by-step explanation:

You add the 5 red and 3 green

8 Mables besides blue

so that's 2/8

simplified 1/4

1/4=0.25

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3 years ago