Pusat lingkaran x² + y² - 2x + 4y - 20 =0 Adalah.....

==Jawaban==

Ingat !
Persamaan lingkaran:
L = x² + y² + Ax + By + C = 0

Pusat:
P = ( -1/2(A), -1/2(B) )

Jadi,,,,,,,
x² + y² - 2x + 4y - 20 =0
A = -2
B = 4

Pusat:
P = ( -1/2(A), -1/2(B) )
P = ( -1/2(2), -1/2(4) )
P = (-1, -2)