Chứng minh rằng
Bài 3 Chứng minh rằng
a (x-y)(x+y)=x^2-y^2
b (x+y)^2=x^2+2xy+y^2
c (x-y)^2 =x^2-2xy+y^2
d (x+y)(x^2-xy+y^2)=x^3+y^3
e (x-y)(x^3+x^2y+xy)=x^4-y^4
a (x-y)(x+y)=x^2-y^2
b (x+y)^2=x^2+2xy+y^2
c (x-y)^2 =x^2-2xy+y^2
d (x+y)(x^2-xy+y^2)=x^3+y^3
e (x-y)(x^3+x^2y+xy)=x^4-y^4