giai bai toan bang cach lap phuong trinh
luc 6h o to thu nhat khoi hanh tu A.den 7h30' o to thu 2 cung khoi hanh tu A duoi theo va kip o to thu nhat luc 10h30'.biet van ttoc o to thu 2 hon van toc o to thu nhat 20km/h.tinh van toc moi o to
giup mk bai nay voi mk can gap
co 2 loai
hay wa vay co j mk hoi bn nho tra loi cho mk nha