2x的平方-3x-5=0,
x1+x2=3/2
x1*x2= -5/2
x1的3次方+x2的3次方
=(x1+x2)(x1²-x1*x2+x2²)
= 3/2[(x1+x2)²-3x1*x2]
= 3/2(9/4+15/2)
= 117/8
x1的5次方+x2的5次方
=(x1²+x2²)(x1³+x2³) - x1²x2³-x1³x2²
=117/8 [(x1+x2)²-2x1*x2 ] - (x1*x2)²(x1+x2)
=117/8 × (9/4 + 5) - 25/4× 3/2
= 3393/32 - 75/8
= 3093/32