Dạng 1. Rút gọn phân thức có đáp án

A=17xy3z434x3y2z=yz32x2

B=y2−xy4xy−7y2=−yx−yy4x−7y=y−x4x−7y

C=x2−255x−x2=x+5x−5−xx−5=x+5−x

D=x2+xz−xy−yzx2+xz+xy+yz=x+zx−yx+zx+y=x−yx+y

E=45x3−x15xx−32=33−x

G=y2−x2x3−3x2y+3xy2−y3=−x+yx−yx−y3=−x−yx−y2

A=ax4−a4xa2+ax+x2=axx3−a3a2+ax+x2=axx−aa2+ax+x2a2+ax+x2=axx−a

B=x3+x2−6xx3−4x=xx2+x−6xx2−4=xx−2x+3xx+2x−2=x+3x+2

C=2a2−2abac+ad−bc−bd=2aa−bac+d−bc+d=2aa−bc+da−b=2ac+d

D=x+a2−4x2a2+9x2+6ax=x+a+2xx+a−2xa2+6ax+9x2=3x+aa−x3x+a2=a−x3x+a

E=y2x−x2y+2x2y+y2x−2=xy2−xy+2xy2+yx−2=−xyx−2y+2xyy+2x−2=−1

F=x2−3x+2x3−1=x−1x−2x−1x2+x+1=x−2x2+x+1

A=x3−5x2+6x−4x2+10x−4=xx2−5x+6x−22x2−5x+2=xx−2x−3−22x−1x−2=−xx−322x−1

B=x2−3xy+2y2x3+2x2y−xy2−2y3=x−yx−2yx2x+2y−y2x+2y=x−yx−2yx+2yx2−y2=x−yx−2yx+2yx−yx+y=x−2yx+2yx+y

C=a+b2−c2a+b+c=a+b+ca+b−ca+b+c=a+b+c

D=a2+b2−c2+2aba2−b2+c2+2ac=a2+2ab+b2−c2a2+2ac+c2−b2=a+b2−c2a+c2−b2=a+b+ca+b−ca−b+ca+b+c=a+b−ca−b+c

F=b−c3+c−a3+a−b3a2b−c+b2c−a+c2a−bMau=a2b−c+b2c−a+c2a−b=a2b−c+b2c−b2a+ac2−bc2=a2b−c+bcb−c−ab2−c2=b−caa−b−ca−b=b−ca−ca−b⇒F=b−c3+c−a3+a−b3−a−bb−cc−a