Rút gọn phân thức: a) 15x^3y^2/35x^6y^4; b) 17xy^3z^4/34x^3y^2z; c) 2x + 6/(x + 3)(x - 2); d) x^2 - 9/x^2 - 6x + 9; e) 9x^2 - 16/3x^2 - 4x

Rút gọn phân thức
a) 15x^3y^2/35x^6y^4
b) 17xy^3z^4/34x^3y^2z
c) 2x + 6/(x + 3)(x - 2)
d) x^2 - 9/x^2 - 6x + 9
e) 9x^2 - 16/3x^2 - 4x
g) x^2 + 4x + 4/2x + 4
h) 2x - x^2/x^2 - 4
Tìm x, biết:
a) x^3 - 9x=0
b) x^3 - 0,25x=0
c) 2x(3x - 5) - (5 - 3x)=0
d) (2x - 1)^2 - (2x + 5)(2x - 5)=18
e) x^3 + 5x^2 - 4x=20