3(4x-y)^2-2(x-y)(x+y)+4(x+3y)^2

Question

3(4x-y)^2-2(x-y)(x+y)+4(x+3y)^2

Answer 1

=3(16x²-8xy+y²)-2(x²-y²)+4(x²+6xy+9y²)=48x²-24xy+3y²-2x²-2y²+4x²+24xy+36y²=
=50x²+37y²