x-y+√(x-y)=sqrt(x-y)(sqrt(x-y)-1)
5x-5y-7sqrt(x-y)=5(x-y)-7sqrt(x-y)=sqrt(x-y)(5sqrt(x-y)-7)
sqrt*x^2-y^2)+sqrt(x-y)=sqrt((x-y)*(x+y))+sqrt(x-y)=sqrt(x-y)(sqrt(x+y)+1)
st+tsqrt(t)+ssqrt(s)+sqrt(st)=s(t+sqrt(s))+sqrt(t)(t+sqrt(s))=(t+sqrt(s))*(s+sqrt(t))