【【【【初一数学题目】】】】】

2(m+4n)^2-(m-n)^2-(m-2n)(m-8n)
=2(m^2+8mn+16n^2)-(m^2-2mn+n^2)-(m^2-10mn+16n^2)
=2m^2+16mn+32n^2-m^2+2mn-n^2-m^2+10mn-16n^2
=28mn+15n^2，
当m＝－1／14，n＝2时,
原式=28mn+15n^2
=28*(-1/14)*2+15*2^2
=-4+60
=56.

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2(m+4n)^2-(m-n)^2-(m-2n)(m-8n)
=2m^2+16mn+32n^2-m^2+2mn-n^2-m^2+10mn-16n^2
=28mn+15n^2
=28*(-1/14)*2+1*2^2
=-4+60
=56