=(4-x^2)/(4-x)(4+x)-(x+1)/(x+4)=((4-x^2)-(x+1)(4-x))/(4-x)(4+x)=(4-x^2-4x+x^2-4+x)/(4-x)(4+x)=-3x/(16-x^2)
=(4-x^2)/(4-x)(4+x)-(x+1)/(x+4)=((4-x^2)-(x+1)(4-x))/(4-x)(4+x)=(4-x^2-4x+x^2-4+x)/(4-x)(4+x)=-3x/(16-x^2)