bai 15
2/(x^2-y^2)√[(3x^2+6xy +3y^2)/ 2 ] +(x-y-√6)/(x-y) =1
<=>2/(x^2-y^2)√[(3(x^2+2xy + y^2))/ 2 ] +(x-y-√6)/(x-y) =1
<=>2/(x^2-y^2)√[(3(x+y )^2 )/ 2 ] +(x-y-√6)/(x-y) =1
x,y >=>x+y>0
<=>2(x+y)/[(x -y )(x+y)].√ (3/2) +(x-y-√6)/(x-y) =1
<=> √ 6/(x-y)+(x-y-√6)/(x-y) =1
<=> (√ 6+x-y- √6)/(x-y) =1
<=> ( x-y )/(x-y) =1
x khac y => x-y khac 0
<=> 1 =1 => dpcm