这两题用因式分解怎么做?

2025-06-21 01:09:08
推荐回答(1个)
回答1:

1解:已知x+y=3,x-y=2;∴x=5/2,y=1/2;
∴2x³y-2xy³=2xy(x+y)(x-y)=2×5/2×1/2(5/2+1/2)(5/2-1/2)=15;
2解:已知xⁿ-yⁿ=(x²+y²)(x+y)(x-y)
∴xⁿ-yⁿ=x⁴-y⁴
∴n=4;