已知m-2的绝对值+(2m-5n+1)^2=0,求（-2m)^2-2m(5n+2m)+3n(3m-2n)的值.
问题描述：
已知m-2的绝对值+(2m-5n+1)^2=0,求（-2m)^2-2m(5n+2m)+3n(3m-2n)的值.
答
m-2=0得m=2
2m-5n+1=0得n=1
（-2m)^2-2m(5n+2m)+3n(3m-2n)
=4m^2-10mn-4m^2+9mn-6n^2
=-mn-6n^2
将m、n代入
原式=-2*1-6*1^2=-2-6=-8
答
m-2的绝对值+(2m-5n+1)^2=0
m-2=0
2m-5n＋1=0
所以
m=2
n=1
所以
（-2m)^2-2m(5n+2m)+3n(3m-2n)
=4m²-10mn-4m²＋9mn-6n²
=-mn-6n²
=-2×1-6×1²
=-2-6
=-8