c^2-16=(c-4)*(c+4)
(2x-1)^2=4x^2-4x+1
(x+3y)^2=x^2+6xy+9y^2
16x^2-25=(4x-5)*(4x+5)
x^2+4x+4=(x+2)^2
(0,2-x)*(0,2+x)=0,04-x^2
(0,5-x)^2=0,25-x+x^2
x^2+9=(x+3)^2-6x
(11-x)*(x+11)=121-x^2
-8x+x^2+16=(x-4)^2
-x^8+y^2=(y-x^4)*(y+x^4)
x^8+y^2=(x^4+y)-2x^4y
25x^2+10x+1=(5x+1)^2
-a^2-2ab-b^2=-(a+b)^2
1-c^3=(1-c)*(1+c+c^2)
-x^2-2x-1=-(x+1)^2
