Rút gọn phân số sau : (2019.5k-2020.3k)/(2019.7k-2020.5k) 03/07/2021 Bởi Rose Rút gọn phân số sau : (2019.5k-2020.3k)/(2019.7k-2020.5k)
$\frac{2019.5k-2020.3k}{2019.7k-2020.5k}$ $=\frac{2019.(5k-3k)-3k}{2019.(7k-5k)-5k}$ $=\frac{2019.2k-3k}{2019.2k-5k}=$$\frac{2k(2019-k)}{2k(2019-3k)}=$ $\frac{2019-k}{2019-3k}$ Bình luận
$\frac{2019.5k-2020.3k}{2019.7k-2020.5k}$ $=\frac{2019.(5k-3k)-3k}{2019.(7k-5k)-5k}$ $=\frac{2019.2k-3k}{2019.2k-5k}=$$\frac{2k(2019-k)}{2k(2019-3k)}=$ $\frac{2019-k}{2019-3k}$