|m|=3,|n|=7,则|m+n|等于

|m|=3,|n|=7,则|m+n|等于
|m|=3,|n|=7,则|m+n|等于

|m|=3,|n|=7,则|m+n|等于
m/2+n/3=7 ----------(1)
m/3-n/4=-7 ----------(2)
(1)式*6得
3m+2n=42----------(3)
(2)式*12得
4m-3n=-84---------(4)
(3)式*3+（4）式*2得
17m=-42
m=-42/17
n=24又12/17