<span> 3a(a+2)-(a+3)^2=3a^2+6a-(a^2+6a-9)=3a^2+6a-a^2-6a+9=2a^2+9</span>
11х-5y+3=0
11х=5у-3
х=(5у-3):11
-5у=-3-11х
у=(-3-11х):(-5)
у=0,6+2,2х