若m+n=3,则2m²+4mn+2n²-6的值为

若m+n=3,则2m²+4mn+2n²-6的值为
若m+n=3,则2m²+4mn+2n²-6的值为

若m+n=3,则2m²+4mn+2n²-6的值为
2m²+4mn+2n²-6
=2(m²+2mn+n²)-6
=2(m+n)²-6
=2x3²-6
=18-6
=12

m+n=3
2m²+4mn+2n²-6
=2(m²+2mn+n²)-6
=2(m+n)²-6
=2*9-6
=18-6
=12

2m²+4mn+2n²-6
=2(m²+2mn+n²)-6
=2(m+n)²-6
=2*3²-6
=18-6
=12