FUx+y=(x+y)(x²-xy+y²)=10•(98-1)=970
(*) x+y=(x²+ y²)²-2x²y² = (x² + y²)2-2(xy)2
(イ),(ウ)の結果から
x+y=982-2.12=9602
()x+y=(x²+ y²)(x³+y³)-x²y³—x³y²
2
13 次式の因数
(x²+ y²)²==
(x²+y²)(x
=(x²+ y²)(x³+y³)=(x+y)(xy)²=x³+x²y³
(ア)~(エ)の結果から
x+y=98.970-10-12=95050 +
x+y=(x+y)(x+y)-xy-xy(x+y)(x
31,3)
=x5+xv4