(a-2)²与丨b+5丨的值互为相反数.
(a-2)²与丨b+5丨是正数
两个正数互为相反数,说明这两个数都为0
说明(a-2)²与丨b+5丨都为0
(a-2)² = 0
丨b+5丨= 0
所以a = 2,b=-5
2a+b = -1