提公因式：已知2x+y=6 x-3y=1 ,求7y(x-3y)²-2(3y-x)³的值._数学解答

提公因式：已知2x+y=6 x-3y=1 ,求7y(x-3y)²-2(3y-x)³的值.

人气：405 ℃　时间：2019-12-22 22:43:10

解答

7y(x-3y)²-2(3y-x)³
=7y(x-3y)²+2(x-3y)³
=(x-3y)²(7y+2x-6y)
=(x-3y)²(2x+y)
=1²*6
=6