已知实数a b c满足方程组

题目

已知实数a b c满足方程组
(1/ab)+(1/ac)=-4-(1/a^2)
(1/bc)+(1/ab)=8-(1/b^2)
(1/ca)+(1/bc)=12-(1/c^2)
求abc
还有一个
x^2-2ax+（a+4）（a-4）=6亅a-x亅
亅为绝对值a-x的绝对值

答案

(1/ab)+(1/ac)=-4-(1/a^2)...1/b+1/c+1/a=-4a(1/bc)+(1/ab)=8-(1/b^2) ...1/c+1/a+1/b=8b(1/ca)+(1/bc)=12-(1/c^2)...1/a+1/b+1/c=12c -4a=8b=12c-a=2b=3c1/a=-1/(3c)1/b=2/(3c)-1/(3c)+2/(3c)+1/c=12c4/(3c)=12cc^2...