1
1)(5+a)/2a²+(1-2a)/a=(5+a+2a-4a²)/2a²=(5+3a-4a²)/2a²
2)4(x+2)/12x²*3x/(x+2)=1/x
3)(m+n)²*8m/[(m-n)(m+n)]=8m(m+n)/(m-n)
2
(y-3)(y+3)/y²*y/(3+y)=(y-3)/y
3/y-(y-3)/y=(3-y+3)/y=(6-y)/y
3
(5a-b)(5a+b)/(5a-b)²*1/[a(5a+b)*2(b-5a)]=-1/[2a(5a-b)²]
a=25 b=56
-1/[50(125-56)²]=-1/(50*4761)=-1/238050