Răspunsuri

2014-05-18T16:32:16+03:00
Folosim formulele
(a-b)²=a²-2ab+b²
a²-b²=(a-b)(a+b)

x²-y²-8x+16=x²-8x+16-y²=(x-4)²-y²=(x-4-y)(x-4+y)