Giải phương trình: a) (x + 1)^2(x + 2) + (x - 1)^2(x - 2) = 12. b) x^4 + x^2 + 6x - 8 = 0. c) (x - 1)^3 + (2x + 3)^3 = 27x^3 + 8. d) (x^2 + 5x)^2 - 2(x^2 + 5x) = 24. e) (x^2 + x + 1)^2 = 3(x^4 + x^2 + 1). f) x^5 = x^4 + x^3 + x^2 + x + 2

Giải phương trình:
a) (x + 1)^2(x + 2) + (x - 1)^2(x - 2) = 12
b) x^4 + x^2 + 6x - 8 = 0
c) (x - 1)^3 + (2x + 3)^3 = 27x^3 + 8
d) (x^2 + 5x)^2 - 2(x^2 + 5x) = 24
e) (x^2 + x + 1)^2 = 3(x^4 + x^2 + 1)
f) x^5 = x^4 + x^3 + x^2 + x + 2
g) (x^2 + x - 2)(x^2 + x - 3)
h) (x - 4)(x - 5)(x - 6)(x - 7) = 1680
i) (x^2 - 6x + 9)^2 - 15(x^2 - 6x + 10) = 1
k) (x^2 +1)^2 + 3x(x^2 + 1) + 2x^2 = 0
l) (2x + 1)(x + 1)^2(2x + 3) = 18
m) (x + 1)^4 + (x - 3)^4 = 82