Formuli: (a+b)²=a²+2ab+b²
(a-b)²=a²-2ab+b²
1)(x+1)²=x²+2.x.1+1²=x²+2x+1
2)(y-2)²=y²-2.y.2+2²=y²-4y+4
3)(a-5)²=a²-10a+25
4)(c+8)²=c²+16c+64
5)(0,2x-0,5a)²=(0,2x)²-2.0,2x.0,5a+(0,5a)²=0,04x²-0,2ax+0,25a²
Naprimer: a²=a.a ( i naoborot)
5²=5.5=25, (-3)²=(-3)(-3)=9, (0,4)²=0,4.0,4=0,16, (6b)²=(6b)(6b)=6.6.b.b=36b² itd.....