Question 262418: x^2+y^2+8x+2y+13=0 Find the center and radius. If someone could explain the steps that would be great!! Answer by drk(1908) (Show Source):
You can put this solution on YOUR website! Here is the original equation
(i)
step 1 - rearrange the terms so that x's are grouped and y's are grouped together.
(ii)
the blanks are waiting for certain numbers
step 2 - take 1/2 of the middle terms and square it
(1/2)*8 = 4 -> 4^2 = 16
(1/2)*2 = 1 -> 1^2 = 1
so, we get
(iii)
notice that the blanks were filled in with the squared numbers.
step 3 - rewrite the x any y trinomial as a binomial squared. Also, simplify the right side to get
(iv)
notice that the constant is 1/2 the middle term.
we have everything we need to find center and radius.
center = (h,k) = (-4,-1)
radius = 2
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