已知(m-2)^2+|2m-n|=0,求m^2-mn+2n^2的值,

已知(m-2)^2+|2m-n|=0,求m^2-mn+2n^2的值,

∵(m-2)²;+|2m-n|=0
∴m-2=0,2m-n=0
∴m=2,n=4
∴m²;-mn+2n²;
=2²;-2×4+2×4²;
=4-8+32
=28