CMR những đẳng thức sau:

a, (x-1) (\(x^2\)+x+1)= \(x^3-1\)

b, (\(x^3+x^2y+xy^2+y^3\)) (x-y)=\(x^4-y^4\)

c,\(\left(x+y+z\right)^2=x^{ }^2+y^2+z^2+2xy+2xz+2yz\)

d,\(\left(x+y+z\right)^3=x^3+y^3+x^3+3\left(x+y\right)\left(y+z\right)\left(z+x\right)\)

Tính nhanh

E=\(4\dfrac{7}{5741}.\dfrac{1}{3759}-\dfrac{4}{3759}.1\dfrac{2}{5741}+\dfrac{1}{3759}+\dfrac{1}{3759.5741}\)