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3 years ago

Write an equation for a circle with a center at (9 -2) and has a radius of 7.

Mathematics

1 answer:

fenix001 [56]3 years ago

8 0

The equation of a circle is given as:

(x-a)^2 + (y- b)^2 = r^2 where (a, b) is the center.

(x-9)^2 = x^2 -18x + 81 - ----(i)
(y+2)^2 =y^2 + 4y +4 ------ (ii)
r^2 = 49 ------ (iii)

Adding equation (i) and (iii)
x^2 + y^2 - 18x + 4y + 85 -----(iv)

Equating equation (iv) and (iii)

x^2 + y^2 - 18x + 4y + 85 = 49

Arrange the equation:

 x^2 + y^2 - 18x + 4y + 36 = 0

I hope this helps

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Answer:

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Step-by-step explanation:

The ratio 4 to 5 means that the left model should have 4 segments shaded (out of 5 given).

The ratio 9 to 10 means that the right model should have 9 segments shaded (out of 10 given).

Compare the shaded regions. If you draw the horizontal line in the left model. then there will be 8 segments shaded (out of 10), this means the ratio 4 : 5 is less than the ratio 9 : 10.

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3 years ago

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Georgia [21]

Answer:

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2 years ago

Simply 8×4³+2×4⁴ giving you answer in the form of 4^b

hram777 [196]

Answer:

4^5

Step-by-step explanation:

8×4³+2×4⁴

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2 years ago

8x - 4y = -12 solve for y

son4ous [18]

Solving an equation means finding a value of a variable that make the equation true. This value is called the solution of the equation. A mathematical equation is just like a balanced equation. Both sides of the equation should be equal at all times. Whatever we do to one side, has to be done on the opposite side.

$8x - 4y = -12$

$4(2x-y)=-12

 
$ $Factor \ out \ the \ common \ term \ 4$

$2x-y=- \dfrac{12}{4}$ $Divide \ both \ sides \ by \ 4$

$2x-y=-3

 

$

$-y=-3-2x$ $Subtract \ 2x \ from \ both \ sides$

$y=3+2x$ $Multiply \ both \ sides \ by \ -1$

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3 years ago

Item 18 you and your friend are selling tickets to a charity event. you sell 7 adult tickets and 16 student tickets for $120. yo

quester [9]

Answer:

Step-by-step explanation:

The two purchases can be written in terms of the cost of an adult ticket (a) and the cost of a student ticket (s):

7a +16s = 120 . . . . . . . . price for the first purchase

13a +9s = 140 . . . . . . . . price for the second purchase

Using Cramer's rule, the value of s can be found as ...

s = (120·13 -140·7)/(16·13 -9·7) = 580/145 = 4

The cost of a student ticket is $4.

_____

Comment on Cramer's Rule

Cramer's rule is particularly useful for systems that don't have "nice" numbers that would make substitution or elimination easy methods to use. If you locate the numbers in the equation, you can see the X-patterns that are used to compute the numerator and denominator differences.

The value of a is (16·140 -9·120)/(same denominator) = 1160/145 = 8. I wanted to show you these numbers so you could see the numerator X-pattern for the first variable.

Of course, graphical methods can be quick and easy, too.

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3 years ago