bài 1:
a/(mình nhìn không rõ)
b/x^2(x+3)/x(x+3)^2=x/x+3
<=>x^2(x+3).(x+3)=x(x+3)^2.x
<=>x^2(x+3)^2=x^2(x+3)^2
c/2-x/2+x=x^2-4x+4/4-x^2
<=>2-x/2+x=(2-x)^2/(2-x)(2+x)
<=>(2-x).(2-x)(2+x)=(2+x).(2-x)^2
<=>(2-x)^2(2+x)=(2-x)^2(2+x)
d/x^3-9x/15-5x=-x^2-3x/5
<=>x(x-3)(x+3)/5(3-x)=x(x+3)/5
<=>x(x-3)(x+3).5=5(3-x).x(x+3)
<=>5x(x-3)(x+3)=5x(x-3)(x+3)
bài 2:
a/2.x^2.y^5/3.x^4.y^2=2.y^3/3.x^2
b/3x(x-y)^3/2x(x-y)^2=3(x-y)/2
c/3.x^2.y+4.x.y^2/6x+8y=xy(3x+4y)/2(3x+4y)=xy/2
d/-3.x^2-6x/4-x^2=3x(x+2)/(2-x)(2+x)=3x/2-x
bài 3:
a/ y^2/x^2+xy +xy/x^2+xy=y^2+xy/x^2+xy=y(y+x)/x(x+y)=y/x
b)x/2x-4 - 2x-2/x^2-2x=x/2(x-2)-(2x-2)/x(x-2)=x^2/2x(x-2)-(4x-4)/2x(x-2)=x^2-4x+4/2x(x-2)=(x-2)^2/2x(x-2)=x-2/2x
c)x-1/x+1 - x+1/x-1 + 4/x^2-1=(x-1)^2/(x-1)(x+1) - (x+1)^2/(x-1)(x+1) + 4/(x-1)(x+1)=x^2-2x+1-x^2-2x-1+4/(x-1)(x+1)=-4(x-1)/(x-1)(x+1)=-4/x+1
d)4/2x-4 - 4x/x^2-4+2x/4+2x=4/2(x-2)- 4x/(x-2)(x+2) + 2x/2(2+x)=8+4x/2(x-2)(x+2) -8x/2(x-2)(x+2) + 2x^2-4x/2(x-2)(x+2)=2(x^2-4x+4)/2(x-2)(x+2)=2(x-2)^2/2(x-2)(x+2)=x-2/x+2
