(3x-4y)(5x-4y)-(7x-8y)(6y-5x)

题目

(3x-4y)(5x-4y)-(7x-8y)(6y-5x)

答案

(3x-4y)(5x-4y)-(7x-8y)(6y-5x)=15x²-12xy-20xy+16y²-（42xy-35x²-48y²+40xy）=15x²+35x²-32xy-42xy-40xy+16y²+48y²=50x²-114xy+64y²祝学习快乐!