Cho biểu thức A= ( căn x / (căn x+3)+(2 căn x)/( căn x-3)-(3x+9)/(x-9)
Giải thích
a)A=xx+3+2xx−3−3x+9x−9 =xx+3+2xx−3−3x+9x−3.x+3=xx−3+2xx+3−3x−9x−3.x+3=x−3x+2x+6x−3x−9x−3.x+3=3x−9x−3.x+3=3x−3x−3.x+3=3x+3
a)A=xx+3+2xx−3−3x+9x−9 =xx+3+2xx−3−3x+9x−3.x+3=xx−3+2xx+3−3x−9x−3.x+3=x−3x+2x+6x−3x−9x−3.x+3=3x−9x−3.x+3=3x−3x−3.x+3=3x+3