how do i write the equation of the circle in standard form. I have to find the center,radius and intercept then graph the circle.  x^2+y^2-4x+18y=-69

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To find the coordinates of the center complete the square for both x and y.

To do this halve the coefficients in front of the terms in x and y which gives -2 and 9 respectively. Considering the expressions

`(x-2)^2 = x^2 - 4x + 4`   and `(y+9)^2 = y^2 + 18y + 81`

we can see that the first 2 terms on the lefthand sides of these two equations give us the terms in `x^2, x, y^2` and `y` in the original equation

`x^2 + y^2 - 4x +18y = -69`

Rearranging the expressions,

`(x-2)^2 - 4 = x^2 - 4x`  and

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