Tìm x

Tìm x:
a) 5(x-2)-x^2+4=0
b)x-3=(3-x)^2
c)x^4-2x^3+x^2-2x=0
d)x^4-4x^3+x^2-4x=0
e)(x^3-x^2)-4x^2+8x-4=0