Ответы и объяснения

2014-02-10T15:03:22+00:00
2014-02-10T15:03:28+00:00
X^2-6x+15 = (x^2-2*3*x+9)+6 = (x-3)^2+6
x^2+x+1 = (x^2+2x+1)-x = (x+1)^2-x