Ex1: Put the verbs in brackets into the Present Simple (do) or Present Continuous ( is doing ) 
1 why ( you look )..................... at me like that?
2 We usually go skiing every year,but this year we (not go).........anywhere
3 the earth (go)................ round the sun
4 she tells me her address but I (not remember)........... it
5 she (prefer)............. tea to coffee

x+1/x^2+x+1 - x-1/x^2-x+1 = 2(x+2)^2/x^6-1

Tìm m để phương trình sau: (m-1)x=m^2-1
a) vô nghiệm
b) vô số nghiệm
c) có nghiệm duy nhất 
cảm ơn đã giúp mik