Răspunsuri

2014-08-14T16:01:27+03:00
2(x²+2x+1)-3(x²-4)+5x²-15x-(9x²-6x+1)=2x²+4x+2-3x²+12+5x²-15x-9x²+6x-1=-5x²-11x+13
am folosit formulele
(a+b)²=a²+2ab+b²
(a+b)(a-b)=a²-b²