(﹣5/12)×8/15×（﹣3/2）×2/3
=5/12×8/15×3/2×2/3
=2/9
（﹣1又1/2）×（﹣1又1/3）×（﹣1又1/4）×（﹣1又1/5）﹣（﹣1又1/6）×（﹣1又1/7）
=3/2×4/3×5/4×6/5×7/6×8/7
=8/2
=4
若|x-1|+|y-2|+|z-3|=0,则根据非负数性质,x-1=0,y-2=0,z-3=0,
x=1,y=2,z=3,所以(x+1)(y-2)(z+3)=2×0×6=0
已知|x+2|+|y-3|=0,则根据非负数性质,x+2=0,y-3=0
x=-2,y=3,所以﹣2又1/2x - 5/3y + 4xy
=5/2×(-2)-5/3×3+4×(-2)×3
=-5-5-24
=-34