Giải phương trình chứa ẩn ở mẫu sau : 2x - 1/x + 1 + 3x - 1/x + 2 = x - 7/x - 1 + 4

2x−1x+1+3x−1x+2=x−7x−1+4x≠±1x≠−2⇔2x−1x+2x−1+3x−1x2−1x+1x−1x+2=x−7x+1+4x+2x2−1x+1x−1x+2⇒2x2+3x−2x−1+3x3−x2−3x+1=x2−6x−7x−2+4x3+2x2−x−2⇔2x3+x2−5x+2+3x3−x2−3x+1=x3−8x2+5x+14+4x3+8x2−4x−8⇔−9x=−3⇔x=13(tm)