Question

What is the equation of the graph?

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Answer 1

Ok.. well first of can you tell me the co ordinates of the centre? from the graph?

Answer 2

Nope, could you walk me through solving the problem. I should have stated I needed guidance.

Answer 3

yes.. if there is any point on a graph.. do you know how to get its co ordinates?

Answer 4

New to this stuff, so I guess not.

Answer 5

ermm. my laptop is about to switch off.. you better google. basic co ordinate geometry!

Answer 6

The x coordinate is the value along the horizontal (left-right) line where the center of the circle is located. From your picture, the x value is -1. Can you understand why? Do you agree with this?
The y coordinate is the value along the vertical (up-down) line where the center of the circle is located. From your picture, the y value is +4. Do you agree with that part?
If so, we can agree the x,y coordinates of the center of the circle are (-1,4)

Answer 7

If we're good so far, the next step is: the standard equation of a circle is
\[(x-h)^{2}+{(y-k)}^{2}=r^{2}\]
So next just substitute the h and k with the x and y coordinates of the center of your circle, so:
\[(x-(-1))^{2}+{(y-4)}^{2}=r^{2}\] or
\[(x+1))^{2}+{(y-4)}^{2}=r^{2}\]
Now all you need is the length of your radius, square it and that's the value you substitute for:
\[r^{2}\]
Questions?