1/3х=5
х=5:1/3
x=15
--------------------------------------------
5*3/1=15
1)3/х+3 + 3/х2-3х + 2х/9-х2=3/х+3 + 3/х(х-3) + 2х/(3-х)(3+х)=3•(х(х-3) + 3•(х+3) -2х•х/х(х+3)(х-3)= 3х2-9х+3х+9-2х2/х(х-3)(х+3)=х2-6х+9/х(х-3)(х+3)=(х-3)2/х(х-3)(х+3)=х-3/х2+3х
3)а^2-b/a-a=0,04+25-0,2=24,84
{y-3x=-5
{2y+5x=23
{y=3x-5
{2(3x-5)+5x=23
6x-10+5x=23
11x=33
x=3
y=3*3-5=9-5=4
Ответ: (3;4)