已知m²+2mn=13,3mn+2n²=21,求2m²+13mn+6n²-44的值

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已知m²+2mn=13,3mn+2n²=21,求2m²+13mn+6n²-44的值

2m²+13mn+6n²-44
=(2m²+4mn)+(9mn+6n²)-44
=2(m²+2mn)+3(3mn+2n²)-44
=2*13+3*21-44
=26+63-44
=45

45

由题2m²+13mn+6n²-44=2(m²+2mn)+3(3mn+2n²)-44=2*13+3*21-44=45

m²+2mn=13
2m²+4mn=26
3mn+2n²=21
9mn+6n²=63
2m²+13mn+6n²-44=26+63-44=45