1
1)(5+a)/2a²+(1-2a)/a=(5+a+2a-4a²)/2a²=(5+3a-4a²)/2a²
2)4(x+2)/12x³*3x/(x+2)=1/x²
3)(m+n)²*8m/(m-n)(m+n)=8m(m+n)/(m-n)
2
3/y-(y-3)(y+3)/y³ *y/(3+y)=3/y-(y-3)/y²=(3y-y+3)/y²=(2y+3)/y²
3
(5a-b)(5a+b)/(5a-b)²*2(b-5a)/a(5a+b)=-2/a=-2/25=-0,08
4
1)2n/(3+n)+9/(n²-3n+9)-(n³-15n²)/(n³+27)=
=(2n³-6n²+18n+27+9n-n³+15n²)/(n³+27)=(n³+9n²+27n+27)/(n³+27)=
=(n+3)³/(n+3)(n²-3n+9)=(n+3)²/(n²-3n+9)
2)(n+3) -9n/(n+3)=(n²+6n+9-9n)/(n+3)=(n²-3n+9)/(n+3)
3)(n+3)²/(n²-3n+9) * (n²-3n+9)/(n+3)=n+3
4)(n+3):(n+3)=1