Question

[Lê Thu Trang]

Bài 1 : dùng hẳng đẳng thức để khai triển và thu gọn

a) \(\left(2x^2+\frac{1}{3}\right)^3\)

b) \(\left(2x^2y-3xy\right)^3\)

c) \(\left(-3xy^4+\frac{1}{2}x^2y^2\right)^3\)

d) \(\left(-\frac{1}{3}ab^2-2a^3b\right)^3\)

e) \(\left(x+1\right)^3-\left(x-1\right)^3-6.\left(x-1\right).\left(x+1\right)\)

f) \(x.\left(x-1\right).\left(x+1\right)-\left(x+1\right).\left(x^2-x+1\right)\)

g) \(\left(x-1\right)^3-\left(x+2\right).\left(x^2-2x+4\right)+3.\left(x-4\right).\left(x+4\right)\)

h) \(3x^2.\left(x+1\right).\left(x-1\right)+\left(x^2-1\right)^3-\left(x^2-1\right).\left(x^4+x^2+1\right)\)

k) \(\left(x^4-3x^2+9\right).\left(x^2+3\right)+\left(3-x^2\right)^3-9x^2.\left(x^2-3\right)\)

l) \(\left(4x+6y\right).\left(4x^2-6xy+9y^2\right)-54y^3\)