Dạng 2: Chứng minh đẳng thức có đáp án

32x−3=3x+62x2+x−6VP=3x+62x2+x−6=3x+2x+22x−3=32x−3=VT

2x+4=2x2+6xx3+7x2+12xVP=2x2+6xx3+7x2+12x=2xx+3xx2+7x+12=2xx+3xx+4x+3=2x+4=VT

x5−1x+1=x4+x3+x2+x+1

x5−1=x+1x4+x3+x2+x+1

2x2+xy−y22x2−3xy+y2=x+yx−yVT=2x2+xy−y22x2−3xy+y2=2x2+2xy−xy−y22x2−2xy−xy+y2=x+y2x−yx−y2x−y=x+yx−yVT=VP⇒dpcm