(a+b+c)^2=(2-1-3)^2=4
a^2+b^2+c^2+2ab+2ac=2^2+(-1)^2+(-3)^2+2*2*(-1)+2*2*(-3)=4+1-4-12=-11
a-1/a=2,
（a-1/a)^2-1/a+6+a=（a-1/a)^2+a-1/a+6=2^2+2+6=12
a=-1/b,b=4,c=-3,
a=-1/4
3a+(a^2)b(c^2)-1/3c^2-3ab+1/3c^3
=3*(-1/4)+(-1/4)*4*(-3)^2)-1/3*(-3)^2-3(-1/4)*4+1/3(-3)^3
=-3/4-9-1/3+3+9
=2-1/12