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The equation of a circle given the center (–4, 4) and raduis r = 5.

User Jared Brown
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1 Answer

16 votes
16 votes

Answer:

x² + y² + 8x - 8y + 7 = 0

Explanation:

Formula: (x - a)² + (y - b)²= r²

where,

a = -4

b = 4

Substitute a and b

( x - (-4))² + (y - 4)² = 5²

(x + 4)² + (y - 4)² = 25

Open Bracket( )

(x + 4) (x + 4) = x² + 4x + 4x + 16

(y - 4) (y - 4) = y² - 4y - 4y + 16

x² + 4x + 4x + 16 + y² - 4y - 4y + 16= 25

Collect Like Terms

x² + y² + 8x - 8y + 16 + 16 - 25 = 0

x² + y² + 8x - 8y + 7 = 0

Therefore,

x² + y² + 8x - 8y + 7 = 0

Is The Equation Of The Given Circle.

User Tejas Bramhecha
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3.7k points