已知x1、x2是方程2x²-3x-5=0的两个根,不解方程,求下列代数式的值：

2x²-3x-5=0
x1+x2=3/2
x1x2=-5/2
x1²+x2²
=(x1+x2)²-2x1x2
=9/4+5
=29/4
|x1-x2|²=(x1+x2)²-4x1x2=9/4+10=49/4
x1²+3x2²-3x2
=x1²+x2²+2x2²-3x2
=29/4+2x2²-3x2
=29/4+5
=49/4