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In this question, given an equation of a sphere, we are asked to find its center and its radius.
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To do that, we need to rewrite this equation in the standard form.
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And in the standard form, it's x minus a squared plus y minus b squared plus z minus c squared equals to r squared.
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A, b and c are the coordinates of the center.
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And r is the radius.
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Now to rewrite our equation in the standard form, we need to complete the squares.
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And to do that, we will take the equation of our sphere to the next page.
01:01
And now we will combine the xs together, x squared minus 8x, and then we will leave some blank space.
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And we will write down the ys together and then also leave some blank space.
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And then we will write down the zs together, but there is only z squared.
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And we want this to be equal to negative 25.
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Now, what should we put in the blanks? in the blanks, what we are going to put.....