Bài 1:
a) 2x(x2 - 4x + 1)
= 2x3 - 8x2 + 2x
b) (16x5y4 - 8x4y3) : 4x2y2 + 2x2y
= 4x3y2 - 2x2y + 2x2y
= 4x3y2
c) \(\dfrac{x+2}{x}\) + \(\dfrac{5-x}{x+2}\)
= \(\dfrac{\left(x+2\right)^2+x\left(5-x\right)}{x\left(x+2\right)}\)
= \(\dfrac{x^2+4x+4+5x-x^2}{x\left(x+2\right)}\)
= \(\dfrac{4+9x}{x\left(x+2\right)}\)
Bài 2:
(3x + 2)(3x - 2) - 9x(x - 1) = 4
9x2 - 4 - 9x2 + 9x = 4
9x = 8
x = \(\dfrac{8}{9}\)