Question

(2015山东)已知|a|=5,|b|=2,|a-b|=b-a,则a+b的值是( ).a.-7b.

(2015山东)已知|a|=5,|b|=2,|a-b|=b-a,则a+b的值是( ).a.-7b.-3c.-7或-3d.以

Answer 1

选：C
∵|a-b|=b-a
∴b≥a
又∵|a|=5,|b|=2
∴a=-5
b=±2
a+b=-7或-3