x²-2=x²-(√2)²=(x-√2)(x+√2)
procedand analog avem
x²-3=(x-√3)(x+√3)
4x²-5=(2x)²-(√5)²= (2x-√5)(2x+√5)
2a²-3b²=(a√2-b√3) (a√2+b√3)
1-3²=1²-3²=(1-3)(1+3)=-2*4=-8; intr-adevar 1-9=-8
9x²-6y²=(3x-y√6)(3x+y√6)
12a²-6y²==6(2a²-y²)=6(a√2-y) (a√2+y)
25y²-8x²=(5y)²-(2√2x)²=(5y-2√2x)(5y+2√2x)
