4c^2+12c+9 25x^2+10x+1 1+a^2-2a^2 4xy+y^2+4x^2 28ab+49a^2+4b^2 (x^2+3y)^2 (o,3a^2+4b)^2 (0,2m^2-5n)^2

4c^2+12c+9=(2c+3)²
25x^2+10x+1=(5х+1)²
1+a^2-2a^2=(1-а)²
4xy+y^2+4x^2=(у+2х)²
28ab+49a^2+4b^2=(7а+2b)²
(x^2+3y)^2=х∧4+6ху+9у²
(o,3a^2+4b)^2=0,09а∧4+2,4а∧2b+16b²
(0,2m^2-5n)^2=0,04m∧4-2mn+25n²