∵a的平方+3a+1=0∴a²+3a=-1 a+3=-1/a a+1/a=-32a的四次方+6a的立方-4a+a分之2-2=2a²(a²+3a)-6a+2a+2/a-2=-2(a²-3a)+2a+2/a-2=2+2a+2/a-2=2(a+1/a)=2x(-3)=-6
