lingkaran x2+y2-4x+6y-b=0 memiliki jari jari 4. Tentukan nilai b!

lingkaran
x² + y² - 4x + 6y - b = 0
A = -4
B = 6
C = -b
r = 4
ditanyakan nilai b?

r² = (A)²/4 + (B)²/4 - C

4² = (-4)²/4 + (6)²/4 - (-b)

16 = (16/4) + (36/4) + b

-b = 4 + 9 - 16

-b = -3

b = 3
maka nilai b = 3