(2a-b)(4a²+b²)(b+a) (2x-y)²-4(x-y)(x+2y)

(2a-b)(4a²+b²)(b+a) (2x-y)²-4(x-y)(x+2y)
(2a-b)(4a²+b²)(b+a) (2x-y)²-4(x-y)(x+2y)

(2a-b)(4a²+b²)(b+a) (2x-y)²-4(x-y)(x+2y)
(2a-b)(4a²+b²)(b+2a)
这里应该是2a吧!
(2a-b)(4a²+b²)(b+2a)
=(2a+b)(2a-b)(4a²+b²)
=(4a²-b²) (4a²+b²)
=16a的4次幂 - b的4次幂
.
(2x-y)²-4(x-y)(x+2y)
=4x²-4xy+y²- 4(x²+xy-2y²)
=4x²-4xy+y²- 4x²-4xy+8y²
=-8xy+9y²