先化简,再求值:2(m+4n)^2-(m-n)^2-(m-2n)(m-8n),其中m=-1/14,n=2

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先化简,再求值:2(m+4n)^2-(m-n)^2-(m-2n)(m-8n),其中m=-1/14,n=2先化简,再求值:2(m+4n)^2-(m-n)^2-(m-2n)(m-8n),其中m=-1/14

先化简,再求值:2(m+4n)^2-(m-n)^2-(m-2n)(m-8n),其中m=-1/14,n=2
先化简,再求值:2(m+4n)^2-(m-n)^2-(m-2n)(m-8n),其中m=-1/14,n=2

先化简,再求值:2(m+4n)^2-(m-n)^2-(m-2n)(m-8n),其中m=-1/14,n=2
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+15*2^2
=-4+60
=56