x²+3x+1=0(x²+3x+1)÷x=0x+3+1/x=0x+1/x=-3(x+1/x)²=(-3)²x²+1/x²+2=9x²+1/x²=7(x²+1/x²)=7²x的4次方+1/x的4次方+2=49x的4次方+1/x的4次方=47
