Question

Jika x+y=2 dan x^2 + y^2 = 6 maka x^3 + y3 = ?

Answer 1

X^2 +y^2 =6
(x+y)^2 -2xy =6
2(2)-2xy =6
4-2xy =6
2xy =-2
xy=-1

x^3 +y^3 =(x+y)^3 -3xy(x+y)
             =(2)^3 -3(-1)(2)
             =8+6=14