Last year, in 2013, many bridges was built so it happen less but in order to stop this, a kind of small car should be invented, people should go to works by buses instead of going by motorbikes... The second one, as you know, the roads in VN is not as big and clean as the roads in the big countries. They're narrow, bumpy and some dirty so it’s really hard for the road users to drive safely. I think we should raise money to make the road in VN better and better. But everyone knows that Vietnamese people are not respect and don’t follow the traffic rules. That’s the biggest reason for everything. They wear the helmet that not strong enough to keep they safe if the accident may happen, they ride too fast on the small roads… The traffic will never can be improve if they keep doing this. At the end, I hope the traffic in VN will improve more

A la 96

B la 224

mik nhé !

x.y = x-y => xy -x+y = 0 => (xy-x)+(y-1)=-1

=> x(y-1)+(y-1)=-1

=>(x+1)(y-1) = -1

=> -1 chia hết cho x+1 và y-1

=> x+1 và y-1 là ước của -1

Nếu x+1 = 1=> x= 0 thì y-1 = -1 => y =0

Nếu x+1 = -1 => x = -2 thì y-1 = 1 => y= 2

Vậy (x;y)= (0;0); (-2;2)

Thi rồi!!!