Thực hiện phép tính (1/2x-1)(2x-3) (5x-2y)(x^2-xy+1) Cảm ơn trước ạ

a) $(\dfrac{1}{2}x-1)(2x-3)$

$=\dfrac{1}{2}x.2x-\dfrac{1}{2}x.3-1.2x+1.3$

$=x^2-\dfrac{3}{2}x-2x+3$

b) $(5x-2y)(x^2-xy+1)$

$=5x(x^2-xy+1)-2y(x^2-xy+1)$

$=5x^3-5x^2y+5x-2x^2y+2xy^2-2y$

$=5x^3-7x^2y+2xy^2+5x-2y$