Question

 Quy đồng mẫu thức các phân thức:1/3x-12;  2/3x+12   ;  3/16-x²       

Answer 1

ta có 3x-12 = 3(x-4)
3x+12=3(x+4)
16-x²=-(x²-16)=-(x-4)(x+4)
=> MTC : -3(x+4)(x-4)
NTP: -(x+4);-(x-4);3
QĐ:
1/3x-12=1/3(x-4)=-(x+4)/-3(x-4)(x+4)=x+4/3(x-4)(x+4)
2/3x+12=2/3(x+4)=-2(x-4)/-3(x+4)(x-4)=2(x-4)/3(x+4)(x-4)
3/16-x²=3/-(x²-16)=3/-(x-4)(x+4)=9/-3(x-4)(x+4)=-9/3(x-4)(x+4)