Cho biểu thức: P=(x-1/x-3+x-3/x+3+4x-2/x^2-9):(1-x+1/x+3).Rút gọn P
Giải thích
P=x−1x−3+x−3x+3+4x−2x2−9:1−x+1x+3DK:x≠±3
=x−1x+3x+3x−3+x−3x−3x+3x−3+4x−2x+3x−3:x+3−x−1x+3
=x2+2x−3+x2−6x+9+4x−2x+3x−3:2x+3
=2x2+4x+3x−3.x+32
=2x2+2x+3x−3.x+32
=x2+2x−3
P=x−1x−3+x−3x+3+4x−2x2−9:1−x+1x+3DK:x≠±3
=x−1x+3x+3x−3+x−3x−3x+3x−3+4x−2x+3x−3:x+3−x−1x+3
=x2+2x−3+x2−6x+9+4x−2x+3x−3:2x+3
=2x2+4x+3x−3.x+32
=2x2+2x+3x−3.x+32
=x2+2x−3