Cho biểu thức: P=(x+2/2-x+2/x+2-x^2+5x/x^2-4 ):(1-x+1/x+2). Rút gọn
Giải thích
P=2+xx−2+2x+2−x2+5xx2−4:1−x+1x+2DK:x≠±2
=2+x2x−2x+2+2x−2x+2x−2−x2+5xx+2x−2:x+2−x−1x+2
=x2+4x+4+2x−4−x2−5xx−2x+2:x+2−x−1x+2
=xx−2x+2:1x+2
=xx−2x+2x+2=xx−2
P=2+xx−2+2x+2−x2+5xx2−4:1−x+1x+2DK:x≠±2
=2+x2x−2x+2+2x−2x+2x−2−x2+5xx+2x−2:x+2−x−1x+2
=x2+4x+4+2x−4−x2−5xx−2x+2:x+2−x−1x+2
=xx−2x+2:1x+2
=xx−2x+2x+2=xx−2