10. Descompuneti in factori :
a)x^2-6x+8 b)x^2-4x+3 c)x^2-3x+2
d)x^2-7x+10 e)x^2-7x+6 f)x^2-8x+7
g)x^2-11x+28 h)x^2-9x+18 i)x^2-8x+15