若|M+1/3|+（N-1/2）²=0,求多项式M²+2M^3N+2M²-2M^3N+3N²=?
问题描述：
若|M+1/3|+（N-1/2）²=0,求多项式M²+2M^3N+2M²-2M^3N+3N²=?
答
m是-1/3
n是1/2
最后算出-1/36
答
∵|M+1/3|+（N-1/2）²=0 ∴M＝-1/3 N＝1/2(非负数和为0，则每个非负数为0)
∴M²+2M^3N+2M²-2M^3N+3N²＝3M²+3N²＝3×（-1/3）²＋3×(1/2)²＝1/3＋3/4＝13/12
答
|M+1/3|+（N-1/2）²=0,
|M+1/3|=0,（N-1/2）²=0,
M=-1/3
N=1/2
M²+2M^3N+2M²-2M^3N+3N²
=M²+2M²+2M^3N-2M^3N+3N²
=3M²+3N²
=3*(-1/3)²+3*(1/2)²
=1/3+3/4
=4/12+9/12
=13/12