(2x + y)(4x2 – 2xy + y2); b) (x2y2 – 3)(3 + x2y2)

minh anhh

$\left(2x+y\right)\left(4x^2-2xy+y^{}\right)$

$=2x\left(4x^2-2xy+y^2\right)+y\left(4x^2-2xy+y^2\right)$

$=8x^3-4x^2y+2xy^2+4x^2y-2xy^2+y^3$

$=8x^3+y^3$

$(x^2y^2-3)(3+x^2y^2)$

$=\left(x^2y^2\right)^2-3^2$

$=x^4y^4-9$.