Răspunsuri

2014-05-03T16:42:58+03:00
X²-y²=(1-rd3)²-(1+rd3)² =1-2rd3+3-1-2rd3-3=-4rd3         x*y=(1-rd3)(1+rd3)=(1-rd3)²=1-2rd3+3= 4-2rd3