∵|a+b-5|与(ab+2)的平方互为相反数,
∴|a+b-5|+(ab+2)²=0
∴a+b-5=0,ab+2=0
∴a+b=5,ab=-2
(3a-2b+ab)-(2a+5ab-3b)
=3a-2b+ab-2a-5ab+3b
=a+b-4ab
=5-4(-2)
=13