Răspunsuri

2014-04-08T15:32:13+03:00
N= (2x-1)^2 - (x-2)^2 + (√3x+1)(1-√3x)
N=(4x
²-2*2x*1+1²)-(x²-2*x*2+4)+√3²-1²
N=4x²-4x+1-x²+4x-4+3-1
N=3x²+3
N∈ Z