(3x-2y)(5x+3y)=3x(5x+3y)-2y(5x+3y)=3x×5x+3x×3y-2y×5x-2y×3y=15x^2+9xy-10xy-6y^2=15x^2-xy-6y^2多说一句：对于两个二项式相乘,其口诀是：前前、后后、里里、外外,即：前边乘以前边+后边乘以后边+里变乘以里边...