m^2-8m-1=0,求m^2+m的二次方分之一-8的值为多少

m^2-8m-1=0,求m^2+m的二次方分之一-8的值为多少

m²-1=8m,
m-1/m=8,
(m-1/m)²=64
m²-2+1/m²=64
∴m²+1/m²=66,
∴m²+1/m²-8=58.