hasil dari x-y = 10 dan xy= 10. nilai x4 + y4 adalah....

[tex](x-y)^2 = 10^2 \\ x^2 + y^2 -2xy=100 \\ x^2 + y^2 - 2(10) = 100 \\ x^2 + y^2 - 20 =100 \\ x^2 + y^2 = 120\\ (x^2 + y^2)^2 = 120^2 \\ = x^4 + y^4 + 2x^2y^2 = 14.400 \\ x^4 + y^4 + 2(xy)^2 =14.400 \\ x^4 + y^4 + 2(10)^2 = 14.400 \\ x^4 + y^4 +200 = 14.400 \\ x^4 + y^4 + 14.200 [/tex]