Question

Please help!Will medal and fan! Question in comments

Answer 1

ok hold on

Answer 2

The answer is A

Answer 3

yea its a megan is right

Answer 4

if you look at it as x-2=0 and y+1=0 you can find x and y

Answer 5

Because x-2 and y+1 are in the brackets

Answer 6

So, I reverse the signs to get the coordinates?

Answer 7

Pretty much

Answer 8

the equation of a circle is
\[(x-x1)^{2}+(y-y1)^{2}=r ^{2}\]
where r is the length of the radius and the centre is (x1,y1)

Answer 9

Thank you. Can you help me with a couple others?

Answer 10

Sure

Answer 11

@MeganKeeping are you there?

Answer 12

Sorry, I'm back now

Answer 13

Okay awesome

Answer 14

The equation of an ellipse is:
\[\frac{ x ^{2} }{ a ^{2} }+\frac{ y ^{2} }{ b ^{2}}=1\]
If b is larger than a, the major axis is the y-axis
If a is larger than b, the major axis is the x-axis

Answer 15

So, it would be A and C?

Answer 16

Yes

Answer 17

Awesome cx I might have a few more in a minute

Answer 18

Look at the equation of the ellipse. a^2 is the larger denominator and b^2 is the smaller denominator. In this case, a^2 = 49 and b^2 = 25
You need to find the value c
c^2 = a^2 - b^2 so c^2 = 24
c=root24
The foci are c either side of the centre on the major axis

Answer 19

If you work out the centre and what axis the major axis lies on, you can work out the foci

Answer 20

The center is (2,-1) and the major axis is the x axis

Answer 21

yes

Answer 22

So, i think it's D

Answer 23

almost!

Answer 24

B?

Answer 25

So the centre is (2,-1) and the foci are a distance c either side of the centre along the x axis.
This means that the y value won't change but you need to add and subtract c to the x value of the centre

Answer 26

Ohhhhh so it's C

Answer 27

c is root24 which is also 2root6

Answer 28

yes it is :)

Answer 29

Awesome cx

Answer 30

The first one is B, I think, and I'm fairly sure the second one is D

Answer 31

The major and minor axes always go through the centre so work out the centre first

Answer 32

The center is (2,-1) so the answer would be D

Answer 33

Yes, that's the first one right

Answer 34

And the second one is A

Answer 35

Yes :)

Answer 36

And the second one is A

Answer 37

I think the answer for this one is A

Answer 38

That looks right :)

Answer 39

The first one is B and the second one is C

Answer 40

I think the first one is A but it looks like you've got the second one right

Answer 41

B and C?

Answer 42

@MeganKeeping are you there?

Answer 43

C and B

Answer 44

the eccentricity is c/a

Answer 45

c^2 = a^2 - b^2 where a^2 is the larger denominator and b^2 is the smaller denominator

Answer 46

And I'm not sure on this one

Answer 47

a^2 = 81
b^2 = 9
so c^2 = 81 - 9 =72
e = c/a
so e= root72/9 = 6root2/9 = 2root2/3 so the answer is D

Answer 48

And then this one is B, I'm pretty sure