М^2+н^2-2мн=(м-н)^2
м^2-16м+64=(м-8)^2
81+м^2+18м=(9+м)^2
1/4а^2+аб+б^2=(1/2а+б)^2
25+х^2-10х=(5-х)^2
9х^2-24ху+16у^2=(3х-4у)^2
100х^2+у^2+20ху=(10х+у)^2
25х^2-20х+4=(5х-2)^2
16-8аб+а^2б^2=(4-аб)^2
х^4+2х^2у+у^2=(х^2+у)^2
4х^4-12х^2у^2+9у^4=
=(2х^2-3у^2)^2
х^4+10х^2+25=(х^2+5)^2
9/16-12а^2+64а^4=
=(3/4-8а^2)^2
1/49а^2+0.2аб^3+0.49б^6=
=(1/7а+0.7б^3)^2