原式=-4a³b²-a³b-5=-4×1×4-1×2-5=-16-2-5=-23
令a=x+1/x则a²=x²+1/x²+2x²+1/x²=a²-2所以f(a)=a²-2所以f(x)=x²-2 a+1所以不等式的解是a+1|x|<1所以-1即-1所以-1所以a+1<=-1a+1<=-1a<=-2a+4>=1a>=-3所以-3<=a<=-2
