Question

[Sách Giáo Khoa]

Áp dụng quy tắc đổi dấu rồi rút gọn phân thức :

a) \(\dfrac{36\left(x-2\right)^3}{32-16x}\)

b) \(\dfrac{x^2-xy}{5y^2-5xy}\)

Answer 1

[Nguyễn Đắc Định]

Answer 2

[Đoàn Như Quỳnhh]

a) \(\dfrac{36\left(x-2\right)^3}{32-16x}=\dfrac{36\left(x-2\right)^3}{16\left(2-x\right)}=\dfrac{36\left(x-2\right)^3}{-16\left(x-2\right)}\)\(=\dfrac{36\left(x-2\right)^3:4\left(x-2\right)}{-16\left(x-2\right):4\left(x-2\right)}\)\(=\dfrac{9\left(x-2\right)^2}{-4}\)

b) \(\dfrac{x^2-xy}{5y^2-5xy}=\dfrac{x\left(x-y\right)}{5y\left(y-x\right)}=\dfrac{x\left(x-y\right)}{-5y\left(x-y\right)}\)\(=\dfrac{x}{-5y}\)