tentukan penyelesaian ataj akar sistem persamaan x²+y²=20 dan x²-y²=12

x^2 + y^2 = 20
x^2 - y^2 = 12
-------------------- -
2y^2 = 8
y^2 = 8/2
y^2 = 4
y = +/- √4
y = +/- 2

x^2 + y^2 = 20
x^2 - y^2 = 12
-------------------- +
2x^2 = 32
x^2 = 32/2
x^2 = 16
x = +/- √16
x = +/- 4
HP = { ( -2,-4), (2, 4) }