1)х^2-16/8x^2::х+4/4х=(x-4)(x+4)*4x/8x^2*(x+4)=x-4/2x

б)= mk^-6/7^5*n^5  *  49^3 n^3k^6/m^-9=m^10 k^07^6/7^5n^2=7m^10/n^2

2) =5^24*2^24/5^25*2^25=1/10

3)16x+1/x+8=0  16x^2+8x+1=0  (4x+1)^2=0 x=-1/4

4)по действиям  1)4-y/4+y  -y/4-y=16-8y+y^2-y^2-4y/(4-y)(4+y)=16-12y/(4-y)(4+y)=4(4-3y)/(4-y)(4+y)

2)4-3y/y+4*(4-y)(4+y)/4(4-3y)=4-y/4