Jika x + y = 1 dan x^2 + y^2 = 7, maka nilai x^3 + y^3 adalah? Sikat suhuuu

(x + y)^2 = 1 x^2 + y^2 + 2xy = 1 7 + 2xy = 1 2xy = -6 xy = -3 (x + y)^3 = x^3 + 3x^2 y + 3x y^2 + y^3 (x + y)^3 = x^3 + y^3 + 3xy(x + y) (1)^3 = x^3 + y^3 + 3(-3)(1) 1 = x^3 + y^3 - 9 x^3 + y^3 = 10

Bab Persamaan Kuadrat
Matematika SMP Kelas VIII

x² + y² = 7
(x + y)² - 2 xy = 7
1² - 2xy = 7
2xy = 1 - 7
xy = -6/2
xy = -3

x^3 + y^3
= (x + y) (x² + y² - xy)
= 1 . (7 - (-3))
= 10