(3x+2y)(2x+3y)-(4x-3y)(3x+4y) 等于多少?

问题描述:

(3x+2y)(2x+3y)-(4x-3y)(3x+4y) 等于多少?

=6x^2+4xy+9xy+6y^2-12x^2+9xy-16xy+12y^2
=-6x^2+6xy+18y^2
=6(-x^2+xy+3y^2)