Thực hiện phép tính

Bài 1: Thực hiện phép tính :
a) 2xy(x2+ xy - 3y2)
b) (x + 2)(3x2 - 4x)
c) (x3 + 3x2 - 8x - 20) : (x + 2)
d) (4x2 – 4x – 4) : (x + 4)
e) (2x3 – 3x2 + x – 2) : (x + 5)
f) (x + y)2 + (x – y)2 – 2(x + y)(x - y)
g) (a + b)3 - (a – b)3 – 2b3
h) (x – y)(x + y)(x2 + y2)(x4 + y4)
i) 2x2(x – 2)+ 3x(x2 – x – 2) –5(3 – x2)
k) (x – 1)(x – 3) – (4 – x)(2x + 1) – 3x2 + 2x – 5
l) (x4 – x3 – 3x2 + x + 2) : (x2 – 1)
Bài 2: Tìm x, biết : a) 9x2 – 49 = 0
b) (x + 3)(x2 – 3x + 9) –x(x – 1)(x + 1) – 27 = 0
c)(x – 1)(x + 2) – x – 2 = 0
d) x(3x + 2) + (x + 1)2 – (2x – 5)(2x + 5) = 0
e) (4x + 1)(x - 2) - (2x -3)(2x + 1) = 7
Bài 3: Rút gọn biểu thức :
a) (2x + 1)2 +(2x + 3)2 – 2(2x + 1)(2x + 3)
b) (2x – 3)(2x + 3) – (x + 5)2 – (x – 1)(x + 2)
c) (24x2y3z2 – 12x3y2z3 + 36x2y2z2) : (-6x2y2z2)
d) (x + 2y)(x2 – 2xy + 4y2) – (x – y)(x2 + xy + y2)
e) (x3 + 4x2 – x – 4) : (x + 4)
f) x2(x + y) + y2(x + y) + 2x2y + 2xy2
g) (x + y)2 + (x – y)2 – 2(x + y)(x - y)
h) (a + b)3 - (a – b)3 – 2b3
i) (x – y)(x + y)(x2 + y2)(x4 + y4)