Question

The equation of the circle concentric with the circle

x² + y² + 8x + 10y – 7 = 0 and passing through the centre of the circle x² + y² – 4x – 6y = 0 is –

• A. x² + y² + 8x + 10y + 59 = 0
• B. x² + y² + 8x + 10y – 59 = 0
• C. x² + y² – 4x – 6y + 87 = 0
• D. x² + y² – 4x – 6y – 87 = 0

Answer 1

Answer: (B)

x² + y² + 8x + 10y – 59 = 0

Answer 2

Centre is (–4, –5) and passes through (2, 3)

Radius = $\sqrt { ( 2 + 4 ) ^ { 2 } + ( 3 + 5 ) ^ { 2 } }$ = 10, eqⁿ of circle

(x + 4)² + (y + 5)² = 10² Ž x² + y² + 8x + 10y – 59 = 0