a)
(x-y)(x+y)=x^2-y^2
b)
(5x-3y)(5x+3y)=(5x)^2-(3y)^2=25x^2-9y^2
c)
(4,5x+y)(4,5x-y)=(4,5x)^2-y^2=20,25x^2-y^2
d)
(\frac{1}{2}x-0,5y)(\frac{1}{2}x+0,5y)=(\frac{1}{2}x)^2-(0,5y)^2=\frac{1}{4}x^2-0,25y^2
e)
(10x-2y)(2y+10x)=(10x-2y)(10x+2y)=100x^2-4y^2
f)
(x+y)(y-x)=(y+x)(y-x)=y^2-x^2
wzór skróconego mnożenia
(a+b)(a-b)=a^2-b^2